Duro and Indestro: The Tools of Progress [Page 3]

Early Indestro Nut and Tap Wrench Set

Indestro made a number of inexpensive open-end wrench sets intended as automobile tool kits or for casual homeowner use. These sets were typically made of stamped and hardened steel, and were held together by center bolts or by small metal holders. The next figures show examples of these sets.

Fig. 63. Early Indestro Nut and Tap Wrench Set, with Inset for Marking Detail, ca. Early to Mid 1920s.

Fig. 63 shows an early example of an Indestro "Nut and Tap" wrench set, marked with the Indestro name in script on each wrench. The set is held together with a stepped-diameter bolt, marked on the end with "Sure Seal Bottle Capper Co." and "Chicago", and with "Mfrs. Indestro Products" in the center.

The wrench sizes in the set are 3/8x7/16 (broken), 1/2x9/16, 5/8x3/4, and 7/8x1 inch. We don't have a specific catalog reference for this early set, and it's possible that there were originally five wrenches.

The Sure Seal Bottle Capper Company marked on the bolt head is an earlier business entity for Indestro Manufacturing, with operations beginning in 1921.

Indestro Nut and Tap Wrench Set

Fig. 64. Indestro Nut and Tap Wrench Set.

Fig. 64 shows another later example of an Indestro "Nut and Tap" wrench set, marked on each wrench with the Indestro name in script.

This set originally consisted of five wrenches (one is missing) covering a size range from 1/4 to 1 inch. The sizes in the set are 1/4x5/16 (missing), 3/8x7/16, 1/2x9/16, 5/8x3/4, and 7/8x1 inch.

The wrenches are held together by a center bolt and wing nut, and the bolt is made with stepped diameters to hold each wrench securely.

Fig. 65. Indestro 7/8x1 Inch Nut and Tap Wrench.

Fig. 65 shows the largest wrench from the "Nut and Tap" set, a 7/8x1 inch open-end wrench of stamped steel construction. The overall length is 6.8 inches, and the finish is cadmium plating.

The square center hole clarifies the meaning of the "Nut and Tap" name, as the holes have been sized to grip the square shank of a threading tap. By using a square hole, Indestro extended the functionality at little or no additional cost.

This wrench set was listed in the 1938 Indestro catalog, but had probably been in production for a number of years by that time.

Indestro 141 1/2x9/16 Box-End Wrench

Indestro produced box-end wrenches of stamped steel construction in a 14x model series, with sizes and models ranging from 3/8x7/16 (140) up through 15/16x1 (145). The wrenches were sold individually or as a six-piece set held together with a bolt and wing-nut.

The next several figures show examples of these wrenches.

Fig. 66. Indestro 141 1/2x9/16 Box-End Wrench.

Fig. 66 shows an Indestro 141 1/2x9/16 wrench of stamped steel construction, marked with "Indestro" and "Chicago, U.S.A." on the shank.

The overall length is 5.4 inches, and the finish is plain steel.

Indestro 142 5/8x11/16 Box-End Wrench

Fig. 67. Indestro 142 5/8x11/16 Box-End Wrench.

Fig. 67 shows an Indestro 142 5/8x11/16 wrench of stamped steel construction, marked with "Indestro" and "Chicago, U.S.A." on the shank.

The overall length is 5.9 inches, and the finish is plain steel.

Indestro 144 13/16x7/8 Box-End Wrench

Fig. 68. Indestro 144 13/16x7/8 Box-End Wrench.

Fig. 68 shows an Indestro 144 13/16x7/8 wrench of stamped steel construction, marked with "Indestro" and "Chicago, U.S.A." on the shank.

The overall length is 6.9 inches, and the finish is plain steel.

Indestro 6 Inch Slip-Joint Thin Combination Pliers

Fig. 68B. Indestro 6 Inch Slip-Joint Thin Combination Pliers, with Inset for Side View, ca. Mid to Late 1920s.

Fig. 68B shows a pair of Indestro 6 inch thin combination pliers of stamped steel construction, stamped with "Indestro Mfg. Co." and "Chicago, U.S.A." on the handle.

The top inset shows a side view of the pliers, showing the dimpled gripping pattern on the handles.

The overall length is 6.2 inches, and the finish is plain steel.

Automotive Service Tools

By the mid 1920s Indestro was producing tools for automotive service, including such items as fixed socket wrenches and valve lifters. Duro Metal Products was probably a year or two behind, but based on their patent activities was producing similar service items by around 1927 or 1928.

Both companies continued producing automotive specialty tools throughout their history, with the mix of particular tools gradually changing as new makes of automobiles presented different requirements for service tools.

Indestro [No. 619] 9/16x3/4 Socket Wrench

Fig. 69. Early Indestro [No. 619] 9/16x3/4 Socket Wrench, with Inset for Marking Detail, ca. Late 1920s to Early 1930s.

Fig. 69 shows an Indestro [No. 619] 9/16x3/4 double-socket wrench, stamped "Indestro Mfg. Co." and "Chicago U.S.A." on the shank. The sockets are broached with 6-point (hex) openings.

The overall length is 9.2 inches, and the finish is plain steel.

The sockets are marked with a five-pointed star on either side of the sizes, a notation frequently seen on early Indestro tools, and the sizes are written as "9 - 16" and "3 - 4".

The 1938 Indestro catalog listed this as a No. 619 double offset socket wrench, part of a group of Model T Ford service tools. It was mentioned for brake shoe support and tranmission cover bolts.

Indestro 1/2x9/16 Socket Wrench

Fig. 70. Early Indestro 1/2x9/16 Socket Wrench, with Insets for Marking Details, ca. Late 1920s to Early 1930s.

Fig. 70 shows an Indestro 1/2x9/16 socket wrench, stamped "Indestro Mfg. Co." and "Chicago U.S.A." on the shank, as shown in the top right inset.

The overall length is 9.1 inches, and the finish is nickel plating, with losses due to rust.

The top left inset shows the five-pointed stars on each side of the fractional size, which is stamped as "1 - 2".

Despite the appearance of being a triple-socket wrench, the small end of the double socket has a circular opening and has not been broached. We're not sure if this was accidental or intentional — maybe for a cheater bar? The large end is marked for the 9/16 opening though.

Duro Metal Products 621 3/4x7/8 Socket Wrench

Fig. 71. Duro 621 3/4x7/8 Socket Wrench, with Insets for Top View and Marking Detail, ca. Late 1920s to Mid 1930s.

Fig. 71 shows an early Duro 621 3/4x7/8 offset socket wrench, stamped with "Duro Metal Products Co." and the model number on the shank.

The overall length is 11.2 inches, and the finish is nickel plating, with extensive losses due to rust.

This wrench was listed in the 1938 Indestro catalog in a group of tools for Ford Model "A" and "B" service. Recommended applications included the spring clips, front and rear engine perch, and radius rod.

Duro Metal Products 624 13/16x13/16 Socket and Box-End Wrench

Fig. 72. Duro 624 13/16x13/16 Socket and Box-End Wrench, with Insets for Side View and Marking Detail, ca. Late 1920s to Mid 1930s.

Fig. 72 shows an early Duro 624 13/16x13/16 socket and box-end wrench, stamped with "Duro Metal Products Co." and the model number on the shank.

The overall length is 11.6 inches, and the finish is plain steel, with extensive pitting due to rust.

The 1935 Indestro catalog lists this wrench for Chevrolet "4" main bearing service.

Duro Metal Products 634 (1/2x9/16)x(5/8x11/16) Socket Wrench

[Early Duro (1/2x9/16)x(5/8x11/16) Socket Wrench]

Fig. 73. Early Duro 634 (1/2x9/16)x(5/8x11/16) Socket Wrench, with Insets for Side View and Marking Detail, ca. Late 1920s to Mid 1930s.

Fig. 73 shows an early Duro 634 quad socket wrench with openings 1/2x9/16 and 5/8x11/16, stamped "Duro Metal Products Co." on the round shank.

The overall length is 10.6 inches, and the finish is nickel plating.

This wrench was listed in the 1938 Indestro catalog in a group of tools for Ford Model "A" and "B" service. Recommended applications included the universal joint, flywheel housing, and cylinder head bolts.

Duro Metal Products 600 1/2x9/16 Socket Wrench

Fig. 74. Duro 600 1/2x9/16 Socket Wrench, with Insets for Top View and Back Side Detail, ca. 1930s.

Fig. 74 shows a Duro 600 1/2x9/16 double-socket wrench, marked "Duro Metal Products Co." with "Chicago, U.S.A." on the back side.

The overall length is 7.6 inches, and the finish is plain steel.

The model 600 wrench was one of the suggested tools for servicing the Chevrolet "6", and was used for manifold, fan bracket, and other applications. This model was no longer listed in the Duro catalogs 38M and 39M, but was listed in the 1938 Indestro catalog.

Duro Metal Products 631 (1/2x5/8)x1/2 Triple Socket Wrench

[Duro Metal Products (1/2x5/8)x1/2 Socket Wrench]

Fig. 75. Duro 631 (1/2x5/8)x1/2 Socket Wrench, with Inset for Marking Detail, ca. late 1920s to Mid 1930s.

Fig. 75 shows a Duro 631 (1/2x5/8)x1/2 triple socket wrench, stamped with "Duro Metal Products Co." and the model number on the shank.

The overall length is 9.9 inches, and the finish is plain steel, with traces of nickel plating.

This triple-socket wrench was listed in the 1938 Indestro catalog as part of a wrench set for Chevrolet "6" service.

[Duro Metal Products] 633 (1/2x5/8)x5/8 Triple Socket Wrench

[Duro Metal Products (1/2x5/8)x5/8 Socket Wrench]

Fig. 76. [Duro] 633 (1/2x5/8)x5/8 Socket Wrench, with Inset for Marking Detail, ca. Mid to Late 1930s.

Fig. 76 shows a [Duro] 633 (1/2x5/8)x5/8 triple socket wrench, stamped with "Made in U.S.A." and the model number on the shank. Although not marked with the manufacturer, this model number is in the sequence used by Duro in earlier years.

The overall length is 9.8 inches, and the finish is plain steel, with traces of nickel plating.

This triple socket wrench was listed in the 1937 Indestro catalog as one of five tools recommended for Model T Ford service. The model 633 wrench is very similar to the classic Walden 1620 "Tomahawk" Wrench, a tool popular for Model T service from before 1920.

This wrench was also listed as a recommended tool for Ford Model "A" and "B" service.

Duro Metal Products 615 21/32 Socket Wrench

Fig. 77. Duro 615 21/32 Socket Wrench, with Inset for Bottom View, ca. Late 1920s to Early 1930s.

Fig. 77 shows a Duro 615 21/32 socket wrench, stamped "Duro Metal Products Co." on the shank.

The overall length is 9.1 inches, and the finish is plain steel.

This wrench was designed for Ford Model "A" and "B" connecting rod applications, and probably dates to the late 1920s or early 1930s. The socket of this wrench is made of hardened carbon steel, but later versions were offered in chrome-vanadium steel.

[Duro] "Chromium Vanadium" 617 9/16 Socket Wrench

Fig. 78. [Duro] 617 9/16 Socket Wrench, ca. 1935 to Late 1930s.

Fig. 78 shows a [Duro] 617 9/16 socket wrench, stamped "Made in U.S.A." on the shank with "Chromium Vanadium" on the socket.

The overall length is 9.0 inches, and the finish is plain steel.

The socket is hot-broached in the style developed by Duro Metal Products, placing the manufacturing date in 1935 or later.

This example is not marked with the company name, but was identified by the model number, general construction, and use of the "Chromium Vanadium" marking. The "Chromium Vanadium" marking suggests that this wrench was likely contract production for Western Auto Supply.

The 1935 Duro catalog lists this as a connecting-rod wrench for Ford V8 service, but notes that it is not guaranteed due to the extremely thin socket walls required by that application.

Duro Metal Products [0626] 3/4 Speeder Socket (Rim) Wrench

Fig. 79. Duro [0626] 3/4 Speeder Socket (Rim) Wrench, with Inset for Marking Detail, ca. 1930s.

Fig. 79 shows a Duro [0626] 3/4 speeder socket wrench, stamped "Duro Metal Products Co." on the shank. The wrench is not marked with a model number, but is listed in the 1938 Duro catalog as a model 0626 rim wrench.

The overall length is 16.4 inches, and the finish is nickel plating.

Duro Metal Products 671 11/16 Ratcheting Box Wrench

Fig. 80. Duro 671 11/16 Ratcheting Box Wrench, with Inset for Side View, ca. Late 1920s.

Fig. 80 shows a Duro 671 11/16 ratcheting box wrench of laminated steel construction, stamped "Duro Metal Products Co." and "Chicago" on the handle.

The overall length is 6.9 inches, and the finish is cadmium plating.

This tool was probably intended for adjusting the brake and back side bands on the Model T Ford. Similar tools were made by various other companies — see for example the Mossberg 645 Ratcheting Box Wrench.

Duro Metal Products No. 2116 Battery Pliers

Fig. 81. Duro Metal Products No. 2116 Battery Pliers.

Fig. 81 shows a pair of Duro 2116 battery pliers, marked "Duro Metal Products Co." and "U.S.A." near the pivot.

The overall length is 8.0 inches, and the finish is cadmium plating.

These pliers are very similar to the Duro-Chrome No. 2115 Battery Pliers, but are made of a less expensive steel.

Indestro No. 410 Universal Drain Plug Wrench

Fig. 82. Indestro No. 410 Drain Plug Wrench, with Inset for Back Side Detail.

Fig. 82 shows an Indestro No. 410 drain plug multi-wrench, marked "U.S.A." with the model number on the back side (see inset).

The overall length is 9.4 inches, and the finish is plain steel.

The wrench features five double-square openings and four hex sizes in two stepped openings. The double-square sizes are 1/2, 9/16, 5/8, 11/16, and 3/4, and the hex sizes are 3/4, 15/16, 1 inch, and 1-1/8.

This tool is described by design patent #D103,579, issued to N.F. McNaught in 1937. The same tool was available as a Duro-Chrome No. 644.

Duro No. 412 Reciprocating Valve Grinder

During the late 1920s Duro applied for at least two patents for reciprocating valve grinders, a popular tool of the time. Typically these tools would alternately advance and then back side the rotation of a shaft to create a randomized grinding pattern.

Fig. 83. Duro No. 412 Reciprocating Valve Grinder, with Insets for Side View and Marking Detail, ca. 1929-1930.

Fig. 83 shows a Duro No. 412 reciprocating valve grinder, marked with "Duro Metal Products Co." and "Chicago, Ill. U.S.A." embossed on the convex cover plate. The flat shaft of the handle is stamped "Duro Metal Products Co." and "Chicago" with a "Patents Pend" notation, as shown in the lower inset.

The pending status refers to patent #1,751,657, filed by E.H. Peterson et al in 1929 and issued in 1930.

Indestro 2021-V8 Valve Guide Punch

Fig. 84. Indestro 2021-V8 Valve Guide Punch, with Insets for Construction and Marking Detail.

Fig. 84 shows an Indestro 2021-V8 valve guide punch, stamped with just the model number.

The overall length is 5.2 inches, and the finish is plain steel.

Hex-Drive Socket Sets

Hex-drive socket sets were among the most popular and best-known products offered by Duro and Indestro. Production of these sets began in the mid 1920s and continued into the 1960s or beyond, although the peak of their popularity was probably in the late 1920s and 1930s. The sets were typically supplied in a compact metal holder, often with a clever design for retaining the pieces in place.

Both Duro and Indestro had multiple patents for various designs for socket set holders, and some of these remained in production for decades.

Indestro [No. 19] 1/2-Hex Drive Socket Set

Fig. 85. Indestro [No. 19] 1/2-Hex Drive Socket Set, with Inset for Top View, ca. Mid to Late 1920s.

Fig. 85 shows an early Indestro [No. 19] 1/2-hex drive socket set in a clever "streamlined" holder resembling a locomotive. The set consists of an Ell-handle, eight sockets, and a screwdriver bit.

The set itself is not marked, but the Ell-handle is stamped "Indestro Mfg. Co." and "Chicago U.S.A." on the shank, as seen in the top inset.

The socket sizes are, from the right, (screwdriver bit), 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 7/8, and 15/16. The sockets are marked only with the fractional sizes.

The sockets have hex (6-point) broachings and a reduced base, and a knurled band is provided to assist with hand turning.

The overall dimensions are 9.4 inches long by 1.5 inches deep by 2.1 inches high. The finish is a thin nickel plating, with extensive losses due to rust.

Although not marked with a patent notation, the holder is covered by patent #1,869,945, filed by H.G. Rice in 1926 and issued in 1932, with assignment to Indestro Manufacturing.

This set was identified as an Indestro No. 19 by a listing in catalog No. 40 from the United Hardware & Tool Corporation. This catalog, acquired as a reprint edition, also lists three other Indestro socket sets as well. (Note though that the 1925 date on the reprint is incorrect. We have a United Hardware 1927 price sheet applying to catalog No. 30, the predecessor to catalog No. 40.)

This set was also listed on page 114 of the 1926 Ford Owners' Supply Book (Eastern edition) from Western Auto Supply, which called it a "Utility Socket Wrench Set". Although the maker is not identified, the illustration shows the distinctive metal holder. The 1926 date makes this the earliest confirmed listing for an Indestro tool.

In the following year the No. 19 set was referred to as the "Dreadnaught" wrench set on page 114 of the 1927 Auto Owners' Supply Book (Eastern edition) from Western Auto Supply. In later years the 1941 Indestro catalogs offered an updated version of this set as the No. 1219, using the same distinctive holder but with 12-point sockets instead of 6-point.

Indestro No. 19 Socket Set in Partially Opened Position

The socket holder for the No. 19 set is rather complex, with three separate movable pieces attached to the base tray. This next figure shows how the pieces move to open the set.

Fig. 86. Indestro No. 19 Socket Set Showing Movement of Pieces.

Fig. 86 shows the Indestro No. 19 socket set with the holder partially open to illustrate the movement of the pieces.

To open the set, the nose piece first folds forward to release the Ell handle. With the Ell handle removed, the tail piece then pivots forward to unlock the rail. Finally, the retaining rail lifts up to free the sockets. (Note the slot in the retaining rail to engage the tip of the screwdriver bit!)

Indestro 1/2-Hex Drive Sockets from No. 19 Set

Fig. 87. Indestro 1/2-Hex Drive Sockets from No. 19 Set, ca. Mid to late 1920s.

Fig. 87 shows the three largest sockets from the Indestro No. 19 set, with sizes from the right of 3/4, 7/8, and 15/16. The sockets are marked with only the fractional size.

The sockets are designed with a stepped base on the larger sizes, with a fairly abrupt transition to the service end diameter. The knurled band in the center of the service end would assist with hand turning.

Indestro No. 28 1/2-Hex Drive Socket Set

Fig. 88. Indestro No. 28 1/2-Hex Drive Socket Set, with Insets for Top View and Marking Detail, ca. Late 1920s to Early 1930s.

Fig. 88 shows an early Indestro No. 28 1/2-hex drive socket set in a clever metal holder, consisting of a ratchet, a screwdriver bit/drive plug, and 8 hex sockets.

The base of the holder is stamped "No. 28" with the Indestro logo and "Indestro Mfg. Co. Chicago U.S.A.", seen as a close-up in the middle inset. The tools and sockets are unmarked except for the fractional sizes on the sockets.

The socket sizes are, from the left, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 7/8, and 15/16. The set is nicely designed so that the size markings are visible from the side.

Although not marked with a patent notice, this set is covered by patent #1,912,725, filed by H.G. Rice in 1929 and issued in 1933. The socket set closely resembles the patent drawings.

The sockets in this set are basically identical to the Indestro No. 19 Sockets shown in a previous figure.

The overall dimensions of the holder are 8.4 inches long by 1.5 inches deep by 1.8 inches high.

The set as acquired was complete except for the drive plug, which was replaced with a later cadmium-plated version.

By 1930 Indestro was offering another set very similar to the No. 28, but with the addition of an Ell-handle. This expanded set is illustrated on page 102 of the 1930 Western Auto Supply (Eastern edition) catalog, where it is referred to as the "Improved Dreadnaught" set. In this larger set the Ell-handle is stacked on top with its short arm plugged into the ratchet, and the tail-piece has been extended so that it can secure the other end of the Ell-handle. (The drive plug is then trapped below the Ell-handle.)

Based on a review of later Indestro catalogs, the expanded set is believed to have been a model No. 35 set, as the later equivalent with 12-point sockets is model No. 1235. We have a No. 1235 set and will display it at some point.

Indestro No. 28 Socket Set in Partially Opened Position

The metal holder for the No. 28 set consists of a base tray with two pieces pivoting on rivets, a front carrier for the ratchet, and a tail piece with a circular recess to secure the drive plug and lock the ratchet carrier. The movement of the pieces can be seen in this next figure.

Fig. 89. Indestro No. 28 Socket Set in Partially Opened Position.

Fig. 89 shows how the metal holder for the Indestro No. 28 set opens up to release the sockets.

First the tail piece is rotated back to release the ratchet carrier, which then can be tipped forward to access the sockets. The ratchet is held in place by friction and can be removed by sliding it forward.

Indestro 1/2-Hex Drive Ratchet from No. 28 Socket Set

Fig. 90. Indestro 1/2-Hex Drive Ratchet from No. 28 Set, ca. Late 1920s to Early 1930s.

Fig. 90 shows the unmarked 1/2-hex drive ratchet from the Indestro No. 28 set.

The overall length is 6.9 inches, and the finish appears to be a very thin nickel plating.

The ratchet appears to be very similar in construction to the Duro No. 673 Ratchet shown in another figure, but the shape of the head is slightly different.

Indestro No. 220 1/2-Hex Drive Socket Set

Fig. 91. Indestro No. 220 1/2-Hex Drive Socket Set, ca. Late 1920s to Early 1930s.

Fig. 91 shows an Indestro No. 220 1/2-hex drive socket set in its steel container, consisting of a ratchet, a screwdriver bit/drive plug, and five of the original six hex sockets. (The 7/8 socket is missing.)

The socket sizes are, from the left, 1/2, 9/16, 5/8, 11/16, and 3/4.

The sockets are marked with the fractional sizes (written in the style "5-8" for 5/8), with a five-pointed star on each side of the size. The ratchet and drive plug are unmarked.

The ratchet closely resembles the No. 28 Set Ratchet shown in another figure.

Fig. 92. Top Cover of Indestro No. 220 Socket Set, ca. Late 1920s to Early 1930s.

Fig. 92 shows the embossed cover of the No. 220 socket set, with the Indestro logo located prominently at the top center.

The text reads "One Set No. 220" and "Auto Socket Wrenches", with "Manufactured by Indestro Mfg. Co." and "Chicago U.S.A." at the bottom.

Two small outline boxes at the left and right margins give the contents of the set, listing a ratchet handle, a screwdriver bit, and socket sizes 1/2, 9/16, 5/8, 11/16, 3/4, and 7/8.

The overall dimensions of the box are 7.2 inches long by 2.1 inches deep by 1.1 inches high. The finish is black paint, now completely lost on the top due to rust.

This set is not as well documented as we would prefer, as it was cobbled together from two partial sets. Both sets were acquired with their original boxes, and one set had drive tools but only three sockets, with none of them appearing to be original. The other set had the five sockets shown here plus some extraneous ones, but no drive tools.

Currently we don't have a catalog reference for this set. The 1930 Western Auto catalog shows a similar "Utility Wrench Set" with the cover hinged at the end, but it's slightly larger and includes an Ell-handle and extra sockets.

Indestro 1/2-Hex Drive Sockets from No. 220 Set

Indestro 1/2-Hex Drive Sockets from No. 220 Socket Set]

Fig. 93. Indestro 1/2-Hex Drive Sockets from No. 220 Set, ca. Late 1920s to Early 1930s.

Fig. 93 shows the five sockets from the No. 220 set, each marked with five-pointed stars on either side of the size markings. The socket sizes are, from the left, 1/2, 9/16, 5/8, 11/16, and 3/4.

The star markings have been observed on a number of relatively early Indestro sockets, suggesting that this was intended as a specific mark for Indestro.

More discussion of this marking can be found at Indestro "Star" Markings in the section on Tool Identification.

The sockets in this set use 1/2 inch hex drive and have hex (six-point) broachings. The sockets were constructed by machining and cold-broaching, and were then hardened, making them impervious to wear but subject to cracking. The band of knurling is coarse enough that it was likely intended to be functional, to allow the socket to be turned by hand.

Duro Metal Products LTX316 1/2-Hex Drive 16-Piece Socket Set

This next figure shows a Duro Metal Products LTX316 socket set, a compact set with an L-T driver and sockets in a tapered metal box. Our set was manufactured around 1930 and so provides a valuable snapshot of Duro socket production at that time.

Fig. 94. 1932 Catalog Listing for Duro Metal Products LTX316 Socket Set.

Fig. 94 shows a catalog listing for the LTX316 set from page 72 of the 1932 J&R Motor Supply Company of St. Louis. The catalog calls it the "Junior" 16-piece socket set, and the illustration clearly shows the Duro L-T handle with a hex-drive bar, and the text notes the 15 sockets.

This is currently our only definite catalog reference for the LTX316 set, although the 1930 Sears Roebuck catalog listed a very similar "Merit" socket set, as will be discussed below.

We were not familiar with J&R Motor Supply prior to acquiring this catalog, but the company appears to have operated with the same model as Western Auto Supply, offering a mix of auto parts, supplies, and tools.

[Duro LTX316 1/2-Hex Drive 16-Piece Socket Set]

Fig. 95. Duro Metal Products LTX316 1/2-Hex Drive 16-Piece Socket Set, ca. 1929-1930.

Fig. 95 shows the Duro Metal Products LTX316 1/2-hex drive socket set in its metal case, consisting of an L-T convertible handle, 12 hex sockets, and three square sockets.

The driver and sockets all use 1/2-hex drive, and the generous assortment of sockets includes hex sizes 5/16, 11/32, 3/8, 7/16, 1/2, 9/16, 19/32, 5/8, 11/16, 3/4, 25/32, and 7/8.

The three square sockets have sizes 5/16, 11/32, and 3/8.

The set is contained in a tapered metal case with a sliding cover, a popular means of storage for socket sets of this type.

Fig. 96. Cover of Duro Metal Products LTX316 Socket Set, ca. 1929-1930.

Fig. 96 shows the top cover from the socket set, a lid that slides into place on the tapered box. The center is stamped with a fancy logo for Duro Metal Products, a design also seen on their valve grinder tools.

The lid is stamped with "LTX" and "316" markings on either side of the Duro logo, providing the model number for the set.

The dimensions of the box are 8.7 inches long by 3.3 inches deep (at the wide end) by 1.2 inches high.

The L-T handle is a convertible design and has been noted previously in our section on Duro patents; the corresponding patent is #1,744,413, filed by E.H. Peterson et al in 1929 and issued in 1930. This particular example is marked "Duro Metal Products Co." and "Chicago U.S.A.", with a "Pat. Pend." notation at the left. Based on the patent filing date, the pending status indicates a manufacturing date of 1929-1930. The bright finish appears to be nickel plating.

A later example of this tool, taken from a very similar socket set, can be seen as the L-T Handle Patent.

To place this socket set in context, the LTX316 set is very similar to a socket set listed in the Sears Roebuck 1929-1930 (Fall-Winter) catalog. The Sears set is listed as the "Merit Tool" 16-Piece Socket Wrench Set, and the description mentions the L-T handle, 15 hex sockets ranging from 5/16 to 7/8, and the metal case with a sliding lid. There are a few minor differences — all hex sockets, the metal case is green, and the tool finish is described as white nickel — but these changes could be easily made during manufacturing. (Actually the description of 15 hex sockets in that size range doesn't sound likely, so possibly the Sears listing just failed to mention the square sockets.) More information on this listing can be found in our summary of the Sears 1929-1930 Fall-Winter Catalog.

The "Merit Tool" brand appears to have been a generic name used by Sears for whatever tools had been selected by their buyers, and may or may not have been actually marked on the tools. One of the advantages of the metal container used for this set is that the cover could be easily stamped with whatever brand the customer wanted. The price for the "Merit Tool" set was just $0.95.

Duro 1/2-Hex Drive L-T Handle from LTX316 Set in Tee-Handle Position

[Duro 1/2-Hex Drive L-T Handle in Tee Position]

Fig. 97. Duro 1/2-Hex Drive L-T Handle from LTX316 Set in Tee Position, ca. 1929-1930.

The L-T handle is normally stored with the Ell-handle inserted into the sheath, as shown in Fig. 95, and it could be used as an Ell-handle in this form if desired.

Fig. 97 shows the L-T handle from the LTX316 set configured in its open position as a Tee-handle. When operation as a Tee-handle is desired, the handle is first removed, then the short arm of the handle is inserted into the sheath. The arm then locks into place against a stamped dimple in the sheath.

The overall length is 7.6 inches in the closed position, and 7.8 inches in the open position.

We haven't found a Duro catalog number for this tool, but the 1935 Indestro catalog offered this as a No. 1306 "Combination Hex L-T Handle", at a $0.36 price. In addition, the Duro version for 1/2 square drive was available as the Duro No. 660 1/2-Drive L-T Handle.

Duro 1/2-Hex Drive Sockets from LTX316 Set

Fig. 98. Duro 1/2-Hex Drive Sockets, ca. 1929-1930.

Most of the sockets in the LTX316 set are marked only with the fractional size, but several of them also have a distinctive D-Trapezoid symbol marked on each side of the size. Fig. 98 shows two of the marked sockets, with sizes 3/8 and 7/16. (Note that the opening shown in the photograph is the 1/2-hex drive end.)

The trapezoid symbol resembles a stylized "D" and has been identified in a catalog as a mark for Duro production. Additional discussion of this D-Trapezoid Marking can be found in our section on Tool Identification.

The sockets have been machined from bar stock, cold-broached, and then hardened, the standard construction method at the time. The decorative band of cross-hatching appears around the top of the larger sockets, but around the base of the smaller sockets shown in the figure, as these have been inverted to simplify the manufacturing. The finish is cadmium plating.

Duro Metal Products 1/2-Hex Drive 16-Piece Socket Set

This next figure shows a Duro socket set similar to the LTX316 Socket Set shown previously, but with a ratchet in addition to the L-T handle.

Fig. 99. Duro Metal Products 1/2-Hex Drive 16-Piece Socket Set, ca. Early 1930s.

Fig. 99 shows a Duro 1/2-hex drive 16-piece socket set, consisting of a No. 673 ratchet, a screwdriver bit/drive plug, an L-T handle, 12 hex sockets from 5/16 to 15/16, and one Alemite (slotted) socket.

The set itself is unmarked, but the ratchet and L-T handle are marked for Duro Metal Products. The tools and sockets are finished with bright nickel plating.

The hex socket sizes are, clockwise from the Alemite socket, 5/16, 11/32, 3/8, 7/16, 1/2, 9/16, 19/32, 5/8, 11/16, 3/4, 7/8, and 15/16. The sockets are marked only with the fractional size, except for one with a D-Trapezoid logo.

Our 16-piece set was acquired in very good condition, but curiously enough the 3/8 socket had been mis-marked as 11/32, an apparent mix-up at the factory. (We thought the socket was missing and so asked the 3/8 socket from the LTX316 set to stand in for the photograph.)

The L-T handle in the set is stamped "Duro Metal Products Co." and "Chicago U.S.A.", and is also marked with patent #1,744,413, filed by E.H. Peterson et al in 1929 and issued in 1930. The patent number marking and hex sockets suggest production in the early 1930s.

The set is contained in a red tapered metal box with a sliding cover. The dimensions are 12.0 inches long by 3.2 inches deep (at the wide end) by 1.5 inches high.

Currently we don't have a catalog reference for this set, but the absence of a company marking on the set suggests it was made as contract production, possibly for sale by Sears Roebuck.

Duro No. 673 1/2-Hex Drive Ratchet from 16-Piece Set

Fig. 100. Duro No. 673 1/2-Hex Drive Ratchet from 16-Piece Set, with Inset for Side View, ca. Early 1930s.

Fig. 100 shows the Duro 673 1/2-hex drive ratchet and drive plug from the 16-piece set. The ratchet is stamped with "Duro Metal Products Co." and the model number on the handle, and the drive plug is unmarked.

The overall length is 7.0 inches, and the finish is nickel plating.

The No. 673 ratchet was an inexpensive model constructed of two identical sheet metal stampings riveted together. (Both sides are marked.)

Duro 1/2-Hex Drive Sockets from 16-Piece Set

Fig. 101. Duro 1/2-Hex Drive Sockets from 16-Piece Set, ca. Early 1930s.

Fig. 101 shows the three largest sockets from the 16-piece set, each stamped with the fractional size. The sizes are, from the right, 3/4, 7/8, and 15/16.

The finish is nickel plating.

Duro No. 500XX 1/2-Hex Drive Double-Hex Socket Set

As double-hex broachings became standard for alloy-steel sockets, Duro/Indestro changed its carbon-steel economy socket sets to double-hex as well. Although the dates are uncertain, the two socket sets below are thought to be representative of Duro/Indestro economy-line double-hex sockets in the early to mid 1930s.

Fig. 102. 1933 Catalog Listing for Duro No. 500XX Socket Set.

Fig. 102 shows a scan from page 144e of the 1933 Ducommun catalog "H", providing an illustration and description for the Duro No. 500 1/2-hex drive socket set, with a No. 500XX option for 12-point sockets.

The No. 500XX set included a No. 673 ratchet, Ell-handle, screwdriver bit, and eight double-hex sockets with sizes from 7/16 to 15/16, all contained in a enameled metal case. The price listed was $2.00 for the No. 500 set and $2.25 for No. 500XX.

Currently we have only an incomplete No. 500XX set to show in the next figure, but have acquired a complete set of somewhat later origin, which will be added as time permits.

Fig. 103. Duro 500 1/2-Hex Drive Handle with Early 12-Point Sockets, ca. Mid 1930s.

Fig. 103 shows a fragment of a Duro No. 500XX set, consisting of a Duro 500 1/2-hex drive handle and several double-hex sockets. The handle is marked "Duro Metal Products Co." and "Chicago U.S.A", along with a notice for patent #1,788,535, issued in 1931.

Originally the set was contained in a distinctive fold-open metal case, which is the subject of the patent mentioned.

We currently have two catalog references for the No. 500XX set, the first of which is the 1933 Ducommun Catalog "H" noted above. The second reference is the 1939 Duro catalog, which lists the Duro No. 500 socket set with contents as above. By this later time double-hex sockets were standard, so no suffix on the model number was necessary.

Duro 673 1/2-Hex Drive Ratchet

Fig. 104. Duro 673 1/2-Hex Drive Ratchet, with Inset for Side View, ca. 1930s.

Fig. 104 shows another 1/2-hex drive Duro 673 ratchet, stamped with "Duro Metal Products Co." and the model number on the handle.

The overall length is 7.0 inches, and the finish is nickel plating, with extensive losses due to rust.

The No. 673 ratchet was an inexpensive model constructed of two identical sheet metal stampings riveted together. (Both sides are marked.) This ratchet was included in several of Duro's socket sets, including the No. 500 set.

Indestro No. 1236 1/2-Hex Drive Double-Hex Socket Set

Fig. 105. Indestro No. 1236 1/2-Hex Drive Double-Hex Socket Set, ca. Mid 1930s to Early 1940s.

Fig. 105 shows a mostly complete Indestro No. 1236 1/2-hex drive socket set, consisting of a ratchet, an Ell handle, a screwdriver bit/drive plug, and seven 12-point sockets, all wrapped up in one of the clever holders that were an Indestro specialty. No model number is marked, but the set matches the No. 1236 set shown in the 1937, 1939, and 1941 Indestro catalogs, with three sockets missing.

The ratchet is stamped "Indestro Mfg. Co." and "Chicago, U.S.A.", but the other pieces are unmarked, except for the fractional sizes on the sockets. The sockets have been simplified to a plain cylindrical form, although they retain the fine cross-hatching at the base.

One of our readers had a question about the identification of this set and we wanted to provide some further information from the catalog listings. The 1937 catalog shows the No. 1236 set as a 13-piece 1/2-hex drive socket set in a metal holder, consisting of a ratchet, Ell handle, screwdriver attachment, and 10 12-point sockets. The socket sizes are given as 7/16, 1/2, 17/32, 9/16, 19/32, 5/8, 11/16, 3/4, 7/8, and 15/16.

The metal holder in the catalog illustration matches our example, except possibly for color, as the catalog is in black and white and no color is specified. We did note though that the illustration shows the two smallest sockets as 5/16 and 3/8, suggesting that the specifications for this set have changed over time. The list price for the No. 1236 set was $1.46, and a No. 1236R set with a reversible ratchet was also available for a $1.74 list price.

One further note may be helpful — in later years Indestro offered a 19-piece No. 1452 set, which was basically a No. 1236 set with an outboard metal holder for a 1/4-hex drive set. It's likely that the holder for the 1/4-hex drive set just clipped on to the larger holder, so that if the two pieces became separated, the 1/2-hex drive part would look like a No. 1236 set, but might be marked as a No. 1452 set.

Indestro No. 2104 3/8-Hex Drive Socket Set

[Indestro No. 2104 3/8-Drive Socket Set]

Fig. 106. Indestro No. 2104 3/8-Hex Drive Socket Set, with Insets for Side View and Marking Detail, ca. 1935-1936.

Fig. 106 shows a 3/8-hex drive Indestro No. 2104 socket set in a metal holder, stamped "Indestro Mfg. Corp. Chicago" and "Pat. Pend." on the Ell handle. The set consists of nine hex sockets with a 3/8-hex Ell handle, all held together in a patented (pending) metal case.

The socket sizes are, from the left, 9/32, 5/16, 11/32, 3/8, 7/16, 15/32, 1/2, 9/16, and 5/8. The sockets are marked with the fractional size and have a band of cross-hatched knurling around the base.

The overall length is 6.8 inches. The finish is cadmium plating for the tools and red paint for the metal holder.

The model number was not marked on this set, but the 1937 Indestro catalog lists this as a No. 2104 "Pee-Wee" socket set.

The patent pending status corresponds to patent #2,065,340, filed by McNaught and Peterson in late 1935 and issued in 1936. The patent describes the metal holder for the set, which includes metal tabs to secure the sockets and a bracket on the back to lock the Ell handle in place (see top inset).

The very similar McNaught and Peterson 1936 patent #2,065,341 describes a socket set holder with a slightly different arrangement for securing the sockets, placing the scalloped tabs in front of the sockets instead of at the back.

Indestro No. 350 1/4-Hex Drive Socket Sets

The next several figures will show examples of Indestro's 1/4-hex drive socket sets.

Fig. 107. 1939 Catalog Listing for Indestro No. 350 Socket Set.

Fig. 107 shows a listing for an Indestro No. 350 1/4-hex drive 8-piece socket set, as found on page 44 of the 1939 Indestro catalog. The set consists of an Ell handle and seven sockets, all held together in a patented metal case.

The sockets in the set have a mix of hexagon, square, and knurled openings to fit the nuts typically found in radios and other small equipment.

The catalog notes that the sets were available in both red and green metal holders, and as it turns out we have an example of each color.

Fig. 108. Indestro No. 350 1/4-Hex Drive Socket Set, with Insets for Side View and Marking Detail, ca. 1935-1936.

Fig. 108 shows an earlier Indestro No. 350 1/4-hex drive 8-piece socket set in its red metal case, consisting of an Ell handle, five hex sockets, one square socket, and one knurled opening socket. The Ell handle is stamped "Indestro Mfg. Corp. Chicago" with a "Pat. Pend." notation, as seen in the lower inset.

The hex socket sizes are, from the left, 1/4, 5/16, 11/32, 3/8, and 7/16. The square socket size is 1/4.

The overall length is 4.3 inches. The handle and sockets are finished with cadmium plating.

The pending notation refers to patent #2,065,340, filed by McNaught and Peterson in late 1935 and issued in 1936. The pending status indicates production in 1935-1936.

Note that the catalog listing incorrectly cites patent #2,065,341 at the top, but the illustration and socket set correspond to the very similar patent #2,065,340. Both patents describe a metal holder for a socket set, with scalloped tabs to secure the sockets and a bracket on the back to lock the Ell handle in place. The two patents differ in the placement of the scalloped tabs, and the interested reader can compare the two patent documents to see the differences.

Fig. 109. Indestro No. 350 1/4-Hex Drive Socket Set, with Inset for Marking Detail, ca. 1937+.

Fig. 109 shows a very similar Indestro No. 350 1/4-hex drive socket set in a green metal case, stamped with the patent number on the back.

The tools and sockets in this set are basically identical to those in the previous figure, but the only marking on the set is the patent number on the back. The handle and sockets are finished with cadmium plating.

The patent notation here correctly refers to patent #2,065,340, filed by McNaught and Peterson in late 1935 and issued in 1936. The patent marking indicates production in 1937 or later.

Indestro Super No. 360 1/4-Hex Drive 6-Piece Handle and Socket Set

Fig. 110. Indestro No. 360 1/4-Hex Drive Handle and Sockets, with Insets for Marking Detail, ca. 1950s to 1960s.

Fig. 110 shows an Indestro Super No. 360 1/4-hex drive handle and five hex sockets, marked with "Indestro Super" and the model number on the handle, with a "Pat. Des. 111026 U.S.A." patent notation.

The socket sizes are, from the left, 1/4, 5/16, 11/32, 3/8, and 7/16.

The overall length is 7.2 inches, and the finish is cadmium plating.

The patent notation refers to design patent #D111,026, filed by W.R. Hosford in late 1938 and issued later that year.

The sockets are secured on the shaft by pinched tabs at the end. To use the tool, the shaft is removed from the handle and then the sockets can be removed.

The No. 360 handle set was offered as early as 1939, but this particular example is of much later production, probably 1950s or 1960s.

Square-Drive Socket Sets

The 1/2-square drive size had emerged as a standard well before 1920 and was the preferred size for most socket wrench applications. The major producers of these tools in the mid 1920s included Blackhawk, Snap-On, and Walden, and by the late 1920s both Duro Metal Products and Indestro Manufacturing had joined the group.

In this article we'll refer to 1/2-square drive as simply 1/2-drive when the meaning is clear from the context.

Indestro 1/2-Drive Hex Sockets

Fig. 111. Early Indestro 1/2-Drive Hex Sockets.

Fig. 111 shows a group of three early 1/2-drive hex sockets from an Indestro socket set. Note that the markings include five-pointed stars on either side of the size, a feature noted on the earlier Sockets from No. 220 Set as well as on the Indestro Socket Wrench shown elsewhere in this article. The production date of this set is unknown, but likely dates from the late 1920s to early 1930s.

Fig. 112. Broaching Detail for Early 1/2-Drive Indestro Sockets.

Fig. 112 shows a closeup of the socket construction, which is similar to those in the No. 220 set. The sockets were first machined, then cold-broached for the six-point hex opening, and finally hardened.

If you look carefully at the upper righthand socket, you can see a small burr left by the broaching, showing that the broaching came after the recess was machined. The centers of the flats also show tooling marks where the socket was drilled out prior to broaching.

The sockets appear to be finished with a thin bright plating.

Early Indestro 1/2-Drive 13-Piece Socket Set

Fig. 113. Early Indestro 1/2-Drive 13-Piece Socket Set, ca. Late 1920s to Early 1930s.

Fig. 113 shows a rare early Indestro 1/2-drive 13-piece socket set in its metal case, consisting of a lever-action ratchet, a drive plug, a T-L handle, and 10 hex sockets from 3/8 to 13/16.

The socket sizes are 3/8, 7/16, 1/2, 9/16, 19/32, 5/8, 11/16, 3/4, 25/32, and 13/16. The sockets are marked with the fractional size with five-pointed stars on each side. The finish is nickel plating.

The ratchet and Ell-handle bar are both marked with "Indestro Mfg. Co." and "Chicago U.S.A." and are finished with nickel plating.

Fig. 114. Top Cover of Indestro 13-Piece Socket Set, ca. Late 1920s to Early 1930s.

Fig. 114 shows the top cover of the 13-piece socket set with its somewhat tattered Indestro decal. This is the standard decal used for Indestro socket sets, and a better example can be seen with the No. 1518 Set.

The overall dimensions are 14.1 inches long by 5.9 inches deep by 1.5 inches high.

The metal case for this set is similar to the case for the Indestro C-V Socket Set from 1931. Note in particular the triangular corral for the sockets.

Currently we don't have a catalog reference for this socket set, but the set is believed to be representative of Indestro's production in the late 1920s to early 1930s. The presence of Indestro's own versions of a lever-action ratchet and T-L handle indicate that this set was produced before Indestro joined forces with Duro Metal Products.

Indestro 1/2-Drive Lever-Action Ratchet from 13-Piece Set

Fig. 115. Indestro 1/2-Drive Lever-Action Ratchet, with Inset for Side View, ca. Late 1920s to Early 1930s.

Fig. 115 shows the Indestro 1/2-drive lever-action ratchet from the 13-piece set, stamped "Indestro Mfg. Co." and "Chicago U.S.A." on the handle.

The overall length is 9.4 inches, and the finish is nickel plating.

The operation of this ratchet is similar to that of the Duro 672 Ratchet or Hinsdale H-1 Ratchet. However, we're unsure of the exact design of the mechanism, since the drive gear is enclosed by a sheet metal sheath.

The embossed sheath enclosing the drive head gives this ratchet a distinctive appearance, which is helpful when trying to attribute catalog illustrations to a specific maker. For example, this ratchet model is illustrated on page 101 of the 1932 Western Auto (Eastern edition) catalog as part of the 47-piece and 36-piece socket sets, along with the Indestro T-L handle.

Indestro 1/2-Drive T-L Handle from 13-Piece Set in Ell-Handle Position

Fig. 116. Indestro 1/2-Drive T-L Handle, with Insets for Side View and Marking Detail, ca. Late 1920s to Early 1930s.

Fig. 116 shows the Indestro 1/2-drive T-L handle from the 13-piece set in its Ell-handle position. The handle bar is stamped "Indestro Mfg. Co." and "Chicago U.S.A." on the shank.

The overall length is 10.2 inches, and the finish is nickel plating.

The close resemblance of this tool to the Hinsdale TL-1 Handle is apparent — in particular the shape of the sheath is very similar. One significant difference is that the Indestro tool has two cross-pins, allowing the arm to lock in two positions. In addition, the Ell-handle bar can be removed from the sheath.

This tool is a significant find, as previously we had been unaware that Indestro had made its own version of a T-L handle. We acquired this tool a number of years ago as part of an early Indestro socket set, but unfortunately overlooked the T-L handle, thinking that it was an interpolation of the Hinsdale TL-1 into the Indestro set.

The Indestro T-L handle was in production as early as 1928, as an example can be seen in a listing for an Indestro No, 600 Socket Set in the 1928 McMaster-Carr catalog.

Indestro 1/2-Drive T-L Handle in Tee-Handle Position

Fig. 117. Early Indestro 1/2-Drive T-L Handle in Tee Handle Position, ca. Late 1920s to Early 1930s.

Fig. 117 shows the Indestro T-L handle from the 13-piece set in its Tee-handle position, with the short arm held in place by a detent ball on the side.

The overall length is 10.1 inches in Tee position, and the finish is nickel plating.

The arm can also be locked in place behind the pin on the end of the sheath, providing a long Ell-handle.

Indestro 1/2-Drive 6-Point Sockets from 13-Piece Set

Fig. 118. Indestro 1/2-Drive 6-Point Sockets from 13-Piece Set, with Inset for Top View, ca. Late 1920s to Early 1930s.

Fig. 118 shows the three largest sockets from the 13-piece set.

The sizes are, from the left, 3/4, 25/32, and 13/16. The sockets are marked with a five-pointed star on each side of the fractional size, a marking convention often seen on early Indestro sockets. The finish is nickel plating.

The inset shows the interior of the 6-point sockets, illustrating the machined and cold-broached construction typical of that time.

Early Duro Metal Products "Double Guarantee" 1/2-Drive Socket Set

This next figure shows an unusually complete and well documented early Duro socket set, referred to as the "Double Guarantee" set for reasons explained below.

Fig. 119. Duro Metal Products "Double Guarantee" 1/2-Drive Socket Set, ca. 1929-1930.

Fig. 119 shows an early Duro Metal Products 1/2-drive socket set, sold through Sears Roebuck and still retaining a Sears "Double Guarantee" paper label on the lid. The set consists of a No. 672 ratchet, a No. 660 L-T convertible handle, an extension, a drive plug, and 15 hex sockets ranging from 5/16 up to 1 inch.

The No. 672 ratchet is stamped "Duro Metal Products Co." and "Chicago" on the handle and has a "Patent Pending" notation, known to be a reference to patent #1,798,481. (This ratchet is a familiar tool and further information can be found in the section for the Duro 672 Ratchet.)

The No. 660 L-T handle also has a patent pending marking, in this case a reference to patent #1,744,413. The pending status for both the ratchet and L-T handle indicates a manufacturing date in the range 1929-1930.

The socket sizes from the front left are 5/16, 3/8, 7/16, 1/2, 9/16, 19/32, 5/8, and 21/32, and from the back left are 11/16, 3/4, 13/16, 7/8, 15/16, 31/32, and 1 inch. The sockets are all stamped with the fractional size, and most are marked with a stylized "D" referred to as the Duro D-Trapezoid logo, although the "D" marking has been omitted on at least one socket.

The socket set is furnished in a green metal box with a hinged cover, with spot-welded dividers to organize the sockets. The box has dimensions 10.9 inches wide by 4.3 inches deep by 1.6 inches high.

This set was reasonably complete as acquired, but was missing the 11/16 socket, which has been replaced from our general inventory. Currently we don't have a Duro catalog reference for this set, but the 1929 Sears catalog lists a very similar set as the "Merit Tool Ratchet Wrench Set". The description of the Sears set includes the same drive tools, with 14 hex sockets from 5/16 to 1 inch, plus a screwdriver socket. If this is the set described in the Sears catalog, the set as pictured has one extra socket (possibly the 31/32 size) and is missing the screwdriver socket.

Duro No. 660 1/2-Drive L-T Convertible Handle from "Double Guarantee" Socket Set

Fig. 120. Duro No. 660 1/2-Drive L-T Convertible Handle, with Inset for Marking Detail, ca. 1929-1930.

Fig. 120 shows the Duro No. 660 1/2-drive convertible L-T handle from the "Double Guarantee" set, configured as a Tee-handle for the photograph. The sheath is stamped "Duro Metal Products Co." and "Chicago U.S.A.", with a "Pat. Pend." notation at the right.

The overall length is 10.6 inches, and the finish is nickel plating.

The pending status refers to patent #1,744,413, filed by E.H. Peterson et al in 1929 and issued in 1930.

The L-T convertible handle consists of a 5/8-diameter Ell-shaped bar with 1/2 square drive studs on each end, together with a sheet metal sheath to form a hand grip. The sheath can be placed either over the short end of the bar to form a Tee-handle, as in the photograph here, or placed on the long end of the bar as a grip and extender.

The sheath can also be completely removed from the bar if desired, and Duro/Indestro sold the Ell-handle bar as a separate tool, as in the Indestro No. 641 Ell Handle.

Duro also supplied the L-T handle in a 1/2-hex drive version, an example of which can be seen as the Duro 1/2-Hex Drive L-T Handle.

Duro No. 660 1/2-Drive L-T Convertible Handle in Ell-Handle Position

Duro No. 660 1/2-Drive L-T Convertible in Ell-Handle Position]

Fig. 121. Duro No. 660 1/2-Drive L-T Convertible Handle in Ell-Handle Position, ca. 1929-1930.

Fig. 121 shows the Duro No. 660 L-T 1/2-drive convertible handle with the sheath installed to form an Ell-handle. The sheath is stamped "Duro Metal Products Co." and "Chicago U.S.A.", with a "Pat. Pend." notation at the right.

The overall length is 10.6 inches, and the finish is nickel plating.

The pending status refers to patent #1,744,413, filed by E.H. Peterson et al in 1929 and issued in 1930.

This photograph need some further explanation, as normally the pinched tab on the Ell-handle bar won't allow the bar to slide all the way into the sheath as shown here. Apparently the former owner of the "Double Guarantee" set expanded the opening of one end of the sheath so that the bar could be stored inside the sheath. It's actually not a bad idea, but the original design intent can be seen in the Extended Ell Handle.

Duro No. 672 1/2-Drive Ratchet from "Double Guarantee" Socket Set

Fig. 122. Duro No. 672 1/2-Drive Ratchet, with Inset for Side View, ca. 1929-1930.

Fig. 122 shows the Duro No. 672 1/2-drive ratchet from the "Double Guarantee" set, stamped "Duro Metal Products Co." and "Chicago", with a "Patent Pending" notation at the right.

The overall length is 9.4 inches, and the finish is nickel plating.

The pending status refers to patent #1,798,481, filed by N.F. McNaught et al in 1928 and issued in 1931.

This tool is a type of lever-action ratchet that depends on the relative motion of the handle and head to lock or release the drive gear, rather than relying on spring-loaded pawls. More information on the Duro 672 Ratchet can be found in another part of this article.

Duro 1/2-Drive 8 Inch Double-Male Extension from "Double Guarantee" Socket Set

Fig. 123. Duro 1/2-Drive 8 Inch Double-Male Extension, ca. 1929-1930.

Fig. 123 shows the unmarked Duro 1/2-drive 8 inch double-male extension from the "Double Guarantee" set.

The overall length is 7.7 inches, and the finish is nickel plating

The extension is constructed from a square bar with a detent ball at each end, with two pinched tabs to act as stops.

Duro 1/2-Drive Large Sockets from "Double Guarantee" Socket Set

Fig. 124. Duro 1/2-Drive Large Sockets from "Double Guarantee" Socket Set, with Inset for Broaching, ca. 1929-1930.

Fig. 124 shows the three largest sockets from the Duro Metal Products "Double Guarantee" 1/2-drive socket set, with sizes (from the left) 15/16, 31/32, and 1 inch. The sockets are stamped with the Duro D-Trapezoid logo on each side of the fractional size, except that the 1 inch socket has only one "D" logo.

The finish is nickel plating.

The larger sockets in the set (from 11/16 up) have a distinctive design with a reduced diameter at the 1/2-square drive end, a pattern mirroring the reduced diameter at the service end for the smaller sockets.

The sockets have a band of cross-hatched knurling at the service end, with the knurling coarse enough to assist with turning a nut by hand. The photograph shows some of the variations in the knurling pattern -- the left socket has a very fine rectilinear grid, and the middle socket has a more coarse diamond cross-hatch pattern. Most of the sockets have a medium-fine cross-hatch pattern similar to the right socket, but at least one socket in the set had no knurling at all, probably due to a production accident.

Duro 1/2-Drive Medium Sockets from "Double Guarantee" Socket Set

Fig. 125. Duro 1/2-Drive Medium Sockets from "Double Guarantee" Socket Set, with Inset for Broaching, ca. 1929-1930.

Fig. 125 shows a group of three medium-sized sockets from the Duro Metal Products "Double Guarantee" 1/2-drive socket set, with sizes (from the left) 1/2, 9/16, and 19/32 inch. The sockets are stamped with the Duro D-Trapezoid logo on each side of the fractional size, except that the 19/32 inch socket is marked with just the size.

The finish is nickel plating.

These smaller sockets have a reduced diameter at the hex service opening, in order to provide clearance for nuts in tight places. The band of cross-hatched knurling appears at the drive end, with the knurling coarse enough to assist with turning a nut by hand.

Early Duro Metal Products 1/2-Drive 23-Piece 6-Point Socket Set

Fig. 126. Duro Metal Products 1/2-Drive 23-Piece Socket Set, ca. 1929-1930.

Fig. 126 shows an early Duro 1/2-drive 23-piece socket set, consisting of a No. 672 ratchet, a No. 660 L-T convertible handle, a drive plug, an extension, and 19 hex sockets ranging from 5/16 to 1-1/4.

The No. 672 lever-action ratchet is stamped "Duro Metal Products Co." and "Chicago" on the handle and has a "Patent Pending" notation, known to be a reference to patent #1,798,481.

The No. 660 L-T handle also has a patent pending marking, in this case a reference to patent #1,744,413.

The pending status for both the ratchet and the L-T handle indicates a manufacturing date in the range 1929-1930.

The socket sizes are, counterclockwise from the left in the second bay, 5/16, 11/32, 3/8, 7/16, 1/2, 17/32, 9/16, 19/32, 5/8, 21/32, 11/16, 3/4, 25/32, 13/16, 7/8, 15/16, 1 inch, 1-1/8, and 1-1/4. The sockets are all stamped with the fractional size, and most are marked with the Duro D-Trapezoid logo on each side of the size.

The sockets and tools were originally finished with nickel plating, but the L-T sheath and ratchet have extensive losses due to rust.

The socket set is furnished in a green metal box with a hinged cover, with spot-welded dividers to organize the sockets. The box has dimensions 11.7 inches long by 6.5 inches deep by 1.6 inches high.

The set as acquired was missing the Ell-handle bar and 3/4 socket, which have been borrowed from other sets for the photograph.

Currently we don't have a catalog reference for this set, and it's possible that it might originally have had additional (or fewer) components. The set is quite similar to the Duro "Double Guarantee" Socket Set shown in another figure, but with four additional sockets.

Duro 1/2-Drive No. 660 L-T Convertible Handle from 23-Piece Socket Set

Fig. 127. Duro No. 660 1/2-Drive Ell Handle from 23-Piece Socket Set, with Inset for Marking Detail, ca. 1929-1930.

Fig. 127 shows the Duro No. 660 1/2-drive L-T handle in its extended Ell-handle position, with the sheath providing a slight increase in leverage. The sheath is stamped "Duro Metal Products Co." and "Chicago U.S.A.", with "Pat. Pend." faintly visible at the left in the inset.

The pending status refers to patent #1,744,413, filed in 1929 and issued in 1930.

This photograph shows the purpose of the pinched tab on the Ell-handle bar, which when wedged between the flanges of the sheath serves to secure the sheath at the end of the handle. Normally the bar won't slide all the way into the sheath, but the former owner of the "Double Guarantee" set apparently expanded the opening of one end of the sheath in that set, allowing the bar to be stored inside the sheath.

Duro 1/2-Drive large Sockets from 23-Piece Socket Set

Duro 1/2-Drive Sockets from 23-Piece Socket Set]

Fig. 128. Duro No. 660 1/2-Drive Sockets from 23-Piece Socket Set, with Inset for Top View, ca. 1929-1930.

Fig. 128 shows the three largest sockets from the Duro 23-piece socket set. The sizes are, from the right, 1 inch, 1-1/8, and 1-1/4. The sockets are marked with the fractional sizes, and the two smaller sockets have D-Trapezoid logos on each side of the size marking.

The finish is nickel plating.

These sockets are very similar to the "Double Guarantee" Sockets shown in another figure. In this set the sockets of size 11/16 and up have a fluted drive end, and sizes 19/32 and smaller have a fluted service end. The two sizes in between, 5/8 and 21/32, have a cylindrical form.

Early Duro No. 825 1/2-Drive 25-Piece Garage Socket Wrench Set

The next figure shows one of the first socket sets acquired for the Alloy Artifacts collection, but which until recently had remained unidentified.

Fig. 129. Duro No. 825 1/2-Drive 25-Piece Garage Socket Wrench Set, ca. 1928-1931.

Fig. 129 shows an early Duro No. 825 1/2-drive socket set, consisting of a No. 672 ratchet, No. 652 short speeder, drive plug, extension, 17 hex sockets from 5/16 to 1 inch, and four square sockets from 1/2 to 3/4.

This set was not marked with a label or decal, but was identified as a No. 825 "25-Piece Garage Socket Wrench Set" by a Duro catalog.

The hex socket sizes are, beginning at the lower right edge, 5/16, 11/32, 3/8, 7/16, 1/2, 17/32, 9/16, 19/32, 5/8, 21/32, 11/16, 3/4, 25/32, 13/16, 7/8, 15/16, and 1 inch.

The four square socket sizes are, from the left, 1/2, 5/8, 11/16, and 3/4. The sockets are stamped with the fractional size flanked by D-Trapezoid logos on each side, and the finish is nickel plating.

The ratchet in the set is basically identical to the Duro No. 672 1/2-Drive Ratchet shown with the previous set. The presence of the patent pending marking indicates a likely production date in 1928-1931.

The set was furnished in a red steel box with a hinged cover, with socket organizers spot-welded along the back and side. The dimensions of the box are 14.4 inches wide by 6.5 inches deep by 1.9 inches high.

This set was acquired with the ratchet and most of the sockets present, but was missing the speeder and extension. The speeder has been filled in from our general inventory, and the extension was borrowed from another early Duro set. A few missing sockets have been replaced from inventory or borrowed from a similar set.

Duro 652 1/2-Drive Short Speeder from No. 825 Set

Fig. 130. Duro 652 1/2-Drive Short Speeder, with Inset for Marking Detail, ca. 1928-1931.

Fig. 130 shows the early 1/2-drive Duro 652 short speeder from the No. 825 set, stamped with "Duro Metal Products Co." and the model number on the shank.

The overall length is 12.6 inches, and the throw is 3.7 inches. The finish is nickel plating.

This speeder is the correct model for the No. 825 socket set, but was acquired as a separate item. Duro frequently omitted the markings from speeders included in their sets, so the markings on this example suggest that it was purchased as an individual tool.

Duro 1/2-Drive Sockets from No. 825 Socket Set

Fig. 131. Early Duro 1/2-Drive Sockets from No. 825 Socket Set, ca. 1928-1931.

Fig. 131 shows a group of three 1/2-drive Duro sockets from the No. 825 socket set. The sockets in the photograph are, from the left, a 25/32 hex socket viewed from the service end, a 5/8 square socket viewed from the service end, and a 1/2 hex socket viewed from the drive end.

The sockets are stamped with the Duro D-Trapezoid logo on each side of the fractional size, and the finish is nickel plating.

These sockets were among the first found with the (then mysterious) D-Trapezoid symbol. Further discussion of the Duro D-Trapezoid Marking can be found in the section on socket identification.

Duro-Bilt 1/2-Drive 20-Piece Socket Set [Duro No. 820FA]

The 1931 Sears Roebuck (Spring-Summer) catalog devotes half a page to "Duro-Bilt" brand socket sets, and the tools in the illustrations closely resemble the known Duro and Indestro socket sets. Although these Duro-Bilt sets are now somewhat hard to find, we have been able to acquire two examples of the sets and can confirm that Duro Metal Products was the manufacturer.

Our first example was listed in the 1931 Sears catalog as a Duro-Bilt "20-Piece Socket Wrench Set", with a note recommending it for Model "A" Ford owners. This same set was also listed in the 1930 Sears (Spring-Summer) catalog.

Fig. 132. Duro-Bilt 1/2-Drive 20-Piece Socket Set, ca. 1929-1930.

Fig. 132 shows a Duro-Bilt 1/2-drive 20-piece socket set, consisting of a Duro No. 660 L-T convertible handle, 15 hex sockets, three square sockets, and a screwdriver socket.

The set is marked with a Duro-Bilt decal on the inside lid, badly chipped but still mostly readable. The decal is printed with "DuroBilt" and "Special Analysis Steel" in the center of the diamond, with "Unconditionally Guaranteed" and "Heat Treated Hardened" along the borders. Readers can refer to the DuroBilt Decal shown with another set for a more readable example.

The No. 660 L-T handle in the set is basically identical to the Duro No. 660 L-T Handle shown in a previous figure. The patent pending status indicates production in 1929-1930.

The hex socket sizes are, from the left in front, 11/32, 3/8, 7/16, 1/2, 9/16, 19/32, and 5/8, and from the left in back are 21/32, 11/16, 3/4, 25/32, 13/16, 7/8, and 15/16. The large hex socket at the back left corner has size 1-1/8.

The three square sockets in the main compartment have sizes, from the left, 3/8, 7/16, and 1/2.

All of the sockets are stamped with the fractional size, but only three of the original sockets are marked with the Duro D-Trapezoid logo. The finish is nickel plating.

The socket set is furnished in a red metal box with a hinged cover, with spot-welded dividers to organize the sockets. The box has dimensions 10.9 inches wide by 4.3 inches deep by 1.6 inches high. (This box has the same size and style as the box used for the Duro "Double Guarantee" Set shown in a separate figure.)

This set was acquired in a nearly complete state, but showed signs of hard use and abuse. The original Ell-handle had been damaged beyond usability and was replaced with an equivalent tool from another set. Two sockets were missing, the 21/32 and 3/4 sizes, and these were replaced from our general inventory. After an electrolytic derusting bath for the L-T sheath and a thorough cleaning for the sockets and box, the set is now fully functional and in good cosmetic condition as well.

Fig. 133. 1933 Catalog Listing for Duro No. 820FA 1/2-Drive Socket Set.

Although our particular set was sold under the Duro-Bilt brand, the set was also available as the Duro No. 820FA socket set.

The scan in Fig. 133 shows an excerpt from page 144F of the 1933 Ducommun catalog "H", illustrating the Duro No. 820FA set with the same components as the Duro-Bilt set here, and noting that it would fit almost all of the nuts on the Model "A" Ford.

The description notes that the sockets are made of "special analysis steel" with a nickel plated finish. (The illustration shows the sockets in a slightly different arrangement, with two of the square sockets in the front row, and the other square socket and the screwdriver in the main bay.) Ducommun offered the set for a $4.00 list price.

Duro 1/2-Drive Screwdriver Socket from "20-Piece" Socket Set

Fig. 134. Duro 1/2-Drive Screwdriver Socket, ca. 1930-1931.

Fig. 134 shows the unmarked Duro 1/2-drive screwdriver socket from the "20-piece" socket set.

The overall height is 1.5 inches, and the width of the blade is 0.5 inches. The finish is nickel plating.

Duro-Bilt 1/2-Drive 36-Piece Socket Set

Our second Duro-Bilt example was listed in the 1931 Sears catalog as the DuroBilt "36-Piece Wrench Set", and the illustration shows a substantial collection of drive tools and sockets in a hinged metal case. (The set is on page 483, for any readers with this Sears catalog.) A check of the contents with the catalog listing showed that our set is nearly complete, with only a few pieces missing. This same set was also listed in the 1930 Sears (Spring-Summer) catalog.

Fig. 135. Duro-Bilt 1/2-Drive 36-Piece Socket Set, ca. 1930-1931.

Fig. 135 shows the Duro-Bilt 1/2-drive 36-Piece socket set as acquired, but with two missing tools filled in from our general inventory.

The ratchet handle in the set is the Duro 672 model discussed in a prior section, and the ratchet is marked with a patent pending notation. The patent status together with the known catalog reference places the manufacturing date right around 1930-1931, and this will prove very helpful in providing a time context for other Duro tools.

Duro-Bilt Decal from 36-Piece 1/2-Drive Socket Set]

Fig. 136. Duro-Bilt Decal from 1/2-Drive "36-Piece" Socket Set.

Fig. 136 shows the Duro-Bilt decal on the inside lid of the case, printed with "DuroBilt" and "Special Analysis Steel" in the center of the diamond, with "Unconditionally Guaranteed" and "Heat Treated Hardened" along the borders.

The decal matches the one shown in the Sears catalog, so the identification of the set is quite certain.

Note that Duro filed its "Duro-Bilt" trademark with a hyphen between the words, but commonly displayed the brand with the two words simply butted together.

The Duro-Bilt sets are quite significant, as these are among the earliest known examples of 1/2-drive socket tools sold by Sears Roebuck, at least for which a reasonable estimate of the manufacturing date can be made. The 1930-1931 origin of the sets predates the Craftsman C-Series and Craftsman "BE" Series socket sets by several years.

Early 12-point Socket Sets

During most of the 1920s sockets were generally made with six-point (or four-point) broachings, but by the late 1920s several companies had started producing 12-point (double-hex) sockets. By the early 1930s both Duro and Indestro had begun producing 12-point sockets as well; although the exact date is not known, we do know that by 1931 Duro and Indestro socket sets were definitely available in 12-point broachings.

The first confirmation comes from the 1931 Sears catalog, which lists several "DuroBilt" brand socket sets that were easily recognizable as Duro production even before we found the "Duro-Bilt" trademark. The high-end set featured chrome-nickel sockets in the standard 6-point broaching, but with 12-point sockets available at a slightly higher price.

A second confirmation is even more direct: by fortunate circumstance we were able to acquire an early Indestro "Chromium Vanadium" 17-piece socket set with a dated sales receipt from 1931. The set consists of a speeder, sliding Tee-handle, ratchet adapter, extensions, universal, and ten 12-point sockets, with most of the pieces being marked "Chromium Vanadium". This set can be seen as the Indestro "Chromium Vanadium" 17-Piece Socket Set along with additional information and photographs.

Although the change to 12-point broachings began with alloy steel socket sets, the carbon-steel sets soon offered 12-point sockets as well. The 1933 Ducommun catalog listed the 1/2-hex drive Duro No. 500XX set with 12-point sockets, and the 1933 Sears Roebuck (Spring-Summer) catalog offered a DuroBilt 40-piece set with "Special Analysis Steel" 12-point sockets.

Indestro "Chromium Vanadium" 1/2-Drive Double-Hex Sockets from 17-Piece Socket Set

Indestro 1/2-Drive Chromium Vanadium Double-Hex Sockets]

Fig. 137. Indestro "Chromium Vanadium" 1/2-Drive Double-Hex Sockets, with Inset for marking Detail, 1931.

Fig. 137 shows a group of nine of the sockets from the Indestro CV 17-Piece Socket Set. (The 7/16 socket didn't match the others, and appears to be a replacement.) All of the sockets shown are marked "Chromium Vanadium" and have a star symbol on each side of the size, a characteristic marking for Indestro sockets.

The sizes are, from the front left, 1/2, 9/16, 5/8, 21/32, and 11/16; and in the back row, 3/4, 13/16, 7/8, and 15/16. The inset shows a typical "Chromium Vanadium" marking.

The sockets have a coarse knurled band around the base, probably intended to help with turning a loose nut by hand.

The socket construction is cold-broached with a bored recess at the base.

If you look carefully at the full-sized photograph, you can see chatter marks typically left by cold broaching.

Indestro No. 1513 1/2-Drive 13-Piece Double-Hex Socket Set

Fig. 138. 1938 Catalog Listing for Indestro No. 1513 Socket Set.

The scan in Fig. 138 from page 33 of the 1938 Indestro catalog illustrates the Indestro No. 1513 1/2-drive 13-piece socket set.

The set consists of an unusual male-female sliding Tee handle, a long extension, a short extension, and ten double-hex sockets ranging from 7/16 to 7/8, all contained in a green metal box with a sliding cover.

Fig. 139. Indestro No. 1513 1/2-Drive 13-Piece Socket Set, ca. 1933 to Mid 1930s.

Fig. 139 shows an Indestro No. 1513 1/2-drive socket set, consisting of a male-female sliding Tee handle, a long extension, a short extension, and ten double-hex sockets. None of the tools in the set are marked.

The socket sizes are, from the left, 7/16, 1/2, 9/16, 5/8, 21/32, 11/16, 3/4, 25/32, 13/16, and 7/8. The sockets are marked only with the fractional sizes.

The model number for our set was not marked, but the set was identified based on the illustration in the 1938 catalog.

Fig. 140. Close-up of Decal for Indestro No. 1513 Socket Set.

Fig. 140 shows a close-up of the small decal on the top cover of the No. 1513 set. The decal shows the Indestro logo and "Chicago U.S.A.", with "Dependable Tools" below.

The overall dimensions of the box are 12.0 inches long by 3.2 inches deep by 1.5 inches high.

The double-male extensions have lengths of 4.6 inches and 7.8 inches. Note that the long extension in the set has a square shank, which was typical of production from the early 1930s and may indicate an early production date for this set.

Our set was acquired in good condition but was missing the 21/32 and 11/16 sockets. (The missing sockets were borrowed from a similar No. 1536 set for the photograph.)

Indestro [No. 659] 1/2-Drive Male-Female Sliding Tee Handle from No. 1513 Set

Fig. 141. Indestro [No. 659] 1/2-Drive Male-Female Sliding Tee Handle, ca. 1933 to Mid 1930s.

Fig. 141 shows the Indestro [No. 659] 1/2-drive sliding Tee handle from the No. 1513 set. Note the unusual male-female design of the sliding Tee head, allowing the tool to be used directly with a double-male extension.

The overall length is 9.0 inches, and the finish is plain steel.

This tool is not marked with a model number, but the 1938 Indestro catalog lists it as a No. 659 sliding Tee handle.

Indestro 1/2-Drive Double-Hex Sockets from No. 1513 Set

Fig. 142. Indestro 1/2-Drive Double-Hex Sockets from No. 1513 Set, ca. 1933 to Mid 1930s.

Fig. 142 shows the three largest sockets from the No. 1513 set.

The sizes are, from the left, 25/32, 13/16, and 7/8. The sockets are marked only with the fractional size.

The finish is cadmium plating.

Note that the service end of these sockets has a slight taper, and as a not unrelated observation, the 3/4 and 7/8 sockets are cracked. Most of the Indestro sets of this era have sockets with straight walls, again suggesting that this set may represent early production.

Indestro No. 1518 1/2-Drive 18-Piece Double-Hex Socket Set

Fig. 143. 1938 Catalog Listing for Indestro No. 1518 1/2-Drive Socket Set.

Fig. 143 shows a listing for the Indestro No. 1518 1/2-drive 18-piece socket set, as found on page 33 of the 1938 Indestro catalog.

The set consists of a lever-action ratchet, a drive plug, an Ell-handle, 12 hex or double-hex sockets, and three square or double-square sockets.

Fig. 144. Indestro No. 1518 1/2-Drive 18-Piece Socket Set, ca. Mid 1930s.

Fig. 144 shows an Indestro No. 1518 1/2-drive socket set, consisting of a lever-action ratchet handle, a drive plug, an Ell handle, 12 hex or double-hex sockets, and three square or double-square sockets.

The inside cover has the standard Indestro decal in unusually good condition, with the Indestro logo at the top followed by "Socket Wrench Sets" and "Manufactured by Indestro Mfg. Co.", with "Chicago U.S.A." at the bottom. The larger Indestro sets were generally marked with this decal.

The ratchet handle is stamped "Chicago U.S.A." with a patent notation, but the other tools are unmarked, and the sockets are marked only with the fractional sizes.

The double-hex socket sizes are 5/16 (hex), 3/8 (hex), 7/16, 1/2, 9/16, 5/8, 21/32, 11/16, 3/4, 13/16, 7/8, and 15/16. The double-square socket sizes are 3/8 (square), 7/16, and 1/2. The finish is cadmium plating.

The set is contained in a metal box with a hinged cover and is finished in Indestro's standard green crackle finish. The overall dimensions are 10.0 inches long by 4.9 inches deep by 1.5 inches high.

[Indestro No. 655] 1/2-Drive Lever-Action Ratchet from No. 1518 Set

Fig. 145. [Indestro No. 655] 1/2-Drive Ratchet from No. 1518 Set, ca. Mid 1930s.

Fig. 145 shows the [Indestro No. 655] 1/2-drive lever-action ratchet from the No. 1518 set, stamped "Chicago U.S.A." and "Pat. No. 1,798,481" on the handle.

The overall length is 9.4 inches, and the finish is cadmium plating.

Although not marked with the maker or model number, this ratchet is listed as a No. 655 in the Indestro catalogs.

The patent notation on the ratchet refers to patent #1,798,481, filed by McNaught and Peterson in 1928 and issued in 1931. This ratchet model was widely used in Duro and Indestro socket sets from the late 1920s onward and will be noted in several other sets here. Typically this ratchet was marked as a Duro No. 672 in Duro socket sets, but the maker and model were omitted for Indestro sets or contract production, as is the case here. The Duro version can be seen as the Duro No. 672 Ratchet.

Indestro [No. 641] 1/2-Drive Ell Handle from No. 1518 Set

Fig. 146. Indestro [No. 641] 1/2-Drive Ell Handle from No. 1518 Set, ca. Mid 1930s.

Fig. 146 shows the unmarked Indestro [No. 641] 1/2-drive Ell handle from the No. 1518 set.

The overall length is 9.5 inches, and the finish is cadmium plating.

Although not marked with the maker or model number, this Ell handle is listed as No. 641 in the Indestro catalogs. The handle is part of the Duro No. 660 convertible L-T handle, but was also sold separately.

This Ell handle can be identified as Duro/Indestro production by the pinched tab visible at about 6 inches from the left, intended to work with the sheath of the Duro No. 660 1/2-Drive L-T Handle.

Indestro 1/2-Drive Double-Hex Sockets from No. 1518 Set

Fig. 147. Indestro 1/2-Drive Double-Hex Sockets from No. 1518 Set, with Inset for Top View, ca. Mid 1930s.

Fig. 147 shows the three largest sockets from the No. 1518 set, each marked only with the fractional size. The sizes are, from the left, 13/16, 7/8, and 15/16.

The finish is cadmium plating.

The inset shows the interior of the sockets, illustrating the cold-broached construction with a bored recess below the broached area.

Note that these sockets have relatively heavy straight walls, without the tapering at the service end seen with the earlier No. 1513 Sockets. These sockets are representative of the Duro/Indestro carbon-manganese sockets from the mid 1930s onward.

Indestro No. 1536 1/2-Drive 12-Point Socket Set

Fig. 148. Indestro No. 1536 1/2-Drive 12-Point Socket Set, ca. Mid 1930s.

Fig. 148 shows an Indestro No. 1536 1/2-drive socket set in a metal case, consisting of a ratchet, speeder, and other drive tools, along with 20 double-hex and eight double-square sockets. The model number for the set was not marked, but the set was identified as the Indestro No. 1536 "36 Piece Master Socket Set" based on the illustration in the 1937 Indestro catalog.

Based on the list of contents in the 1937 catalog, this set is nearly complete, missing only the short extension (ratchet plug), screwdriver bit, and the valve grinder attachment. (This set also includes one extra double-hex socket.)

The catalog description lists the hex socket sizes as 5/16, 11/32, 3/8, 7/16, 1/2, 17/32, 9/16, 19/32, 5/8, 21/32, 11/16, 3/4, 13/16, 7/8, 15/16, 31/32, 1 Inch, 1-1/16, 1-1/8, and 1-1/4, all double-hex except for the three smallest. The double-square socket sizes are 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, and 7/8.

The empty corral in the upper left corner of the case was for six drain plug sockets, apparently an optional item for the early versions of this set. By 1937 the illustration showed the small corral holding some of the smaller hex sockets, with the main corral having been reduced in size.

Fig. 149. Decal for Indestro No. 1536 Socket Set.

Fig. 149 shows the Indestro decal on the lid of the No. 1536 set, though it's a bit difficult to read due to the glare from the finish. The larger Indestro sets were generally marked with this decal, either on the top or on the inside of the lid. In either position though the somewhat fragile decal was easily damaged, and often only a fragment remains.

A better example of the decal can be seen with the Indestro No. 1518 Socket Set.

One additional note regarding this set: of the tools in the set, only the ratchet handle had an identification mark, and that was only the patent number for the ratchet. If the decal with the Indestro logo case were lost or obliterated, or the tools dispersed from the case, it would be difficult to identify them as part of an Indestro set.

This set provides a good example of the carbon-manganese steel economy grade socket sets sold by Duro and Indestro in the 1930s. The 1937 catalog price for the No. 1536 set was just $6.40, less than half the price of a similar "Super Quality" chrome-vanadium steel set.

Although the sockets in this set are marked only with the size, the Indestro catalogs did assign model numbers to the series, similar to the numbering used for the Duro D-Trapezoid sockets described above. The 1937 Indestro catalog (p. 26) shows these sockets in a table "Master Sockets", with model numbers of the form 66xx where xx is the size in 32nds, e.g. 6624 for the 3/4 size. Similar to the case for Duro, the square and double-square sockets have a "-S" appended, e.g. 6624-S.

Indestro 1/2-Drive 13 Inch Speeder

Fig. 150. Indestro 1/2-Drive 13 Inch Speeder, with Inset for Marking Detail, ca. Late 1920s to 1930s.

Fig. 150 shows an Indestro 1/2-drive 13 inch speeder, stamped "Indestro Mfg. Corp." and "Chicago U.S.A." on the shank.

The overall length is 13.7 inches, and the throw is 4.0 inches. The finish is plain steel, with light pitting due to rust.

This speeder is similar to the Indestro C-V Speeder included in a 1931 "Chromium Vanadium" socket set, but is not marked to indicate alloy steel.

Indestro [642] 1/2-Drive Valve Grinding Adapter

Fig. 151. Indestro [642] 1/2-Drive Valve Grinding Adapter, ca. 1930s.

Fig. 151 shows a 1/2-drive Indestro [642] valve grinding adapter, unmarked but identified by an illustration in the 1937 Indestro catalog.

The overall length is 2.5 inches, and the finish is cadmium plating.

This tool is typical of the valve grinding adapters often included in early socket sets. The points on the blades fit into small indentations on the head of the valve, and the slotted blades can be adjusted to fit different valve sizes by means of two machine screws.

Indestro No. 657 1/2-Drive "Master" Ratchet

Fig. 152. Indestro No. 657 1/2-Drive Ratchet, with Insets for Side View and Marking Detail, ca. 1930s.

Fig. 152 shows a 1/2-drive Indestro No. 657 "Master" ratchet, stamped "Indestro Mfg. Corp." and "Chicago U.S.A." on the shank.

The overall length is 10.1 inches, and the finish is cadmium plating.

The Indestro catalogs refer to this model as the "Master Ratchet Handle".

Although not marked with a patent, this ratchet appears to be of the same design as the Hinsdale H-1 Ratchet, which is described by the McDonough 1927 patent #1,650,085. In this design the pawl is actually a hardened point at the end of the handle, and the head assembly pivots to lock or release the drive gear.

Indestro "Select Steel" Tools

The 1937 "Streamlined" trademark was the starting point for one of Indestro's most successful product lines, the "Select Steel" line of tools offering stylish designs at economy prices. These tools were first offered in the 1937 Indestro catalog and initially consisted of open+box, open-end, and short angled box-end wrenches. Offset box-end wrenches in long and short patterns were added in 1938.

The 1937 catalog illustrates the open-end and angled box-end wrenches with streamlined panels, but the open+box wrenches are shown with triangular-shaped depressed panels, an older design predating the "Streamlined" trademark. Within a short time the open+box wrenches were also converted to streamlined panels.

In this section we'll explore the development of the "Select Steel" line from its beginning in 1937 through 1945, and then will continue discussion of the postwar period in a later section on The "Select Steel" Brand.

Alloy Steel vs. Select Steel

Although these tools are named for the familiar "Drop Forged Select Steel" marking forged into the tools, when Indestro first started production in 1937 the line was referred to as "Special Alloy" tools. Pages 10 through 14 of the 1938 Indestro catalog offered "Special Alloy Steel" box-end, open-end, and open+box wrenches, both as individual tools or in "Klip Tite" sets with a small metal holder.

Fig. 153. 1938 Catalog Listing for Indestro Open-End Wrenches.

The page for the open-end engineer's wrenches even had "Drop Forged Alloy Steel" as a heading, as can be seen in the scan in Fig. 153, taken from page 13 of the 1938 Indestro catalog.

In the 1930s carbon steel for less expensive tools generally meant a tool steel such as AISI 1040 (0.6 to 0.9 percent Mn) or a carbon-manganese steel such as AISI 1340 (1.6 to 1.9 percent Mn).

This type of steel was less expensive than chrome-alloy steel, but still offered greatly improved performance when compared to the sometimes brittle carbon steel of the early 1920s or before.

Since manganese is a metal, it could be argued that technically carbon-manganese steel is an alloy steel, but most tool companies did not refer to it as such, and instead reserved the "Alloy Steel" designation for their higher-priced chrome alloy tools.

Indestro used the "Alloy Steel" description only briefly. In the 1939 catalog the heading of the Engineer's Wrench table had changed to "Drop Forged Selected Steel", and presumably the forged-in markings followed suit. This provides us with a fairly precise 1937-1938 manufacturing date estimate for the wrenches with the "Alloy Steel" marking.

Production and Marking Characteristics

One of the most notable facets of the "Select Steel" line was the high quality of the production, especially considering that this was an economy line of tools. By the mid 1930s Duro/Indestro's forging operations had become extremely skilled at die-making, and the results can be seen in the precisely formed panels and crisply executed forged-in markings of the tools.

The early markings on the tools placed "Indestro" and "Chicago U.S.A." forged into one side, with "Drop Forged Alloy Steel" on the back side, soon to be replaced by "Drop Forged Select Steel". We refer to this early group as the Indestro "Chicago" series, to distinguish them from tools with later markings.

The presence of the forged-in company name means that Indestro at least initially viewed the "Select Steel" line as Indestro-only products, without considering the possibility of contract production or private branding. But their intentions seem to have changed fairly soon — when the long and short offset box wrenches were added in 1938, these models appear to have omitted the Indestro marking from the beginning.

In the course of researching this article, we were somewhat surprised to find not even one example of an offset box wrench with the Indestro "Chicago" marking, despite having gathered a rather large number of wrenches. (We also have not observed any offset box wrenches with an "Alloy Steel" marking.)

In the absence of Indestro "Chicago" offset box wrenches, we next looked for examples with plain steel finishes that would indicate 1941-1945 wartime production. A number of such wrenches were found, and all were marked with "Made in U.S.A." forged into one side, with "Forged Select Steel" forged into the back side. In addition, no wrenches of plausible earlier construction have been found with different markings, strongly suggesting that these were the markings in effect since 1938.

The generic markings on the offset box wrenches show that these tools were produced with contract production in mind from the beginning. Thus it's not surprising that the other styles — angled box, open-end, and open+box wrenches — were eventually changed to generic markings as well. However, we haven't yet found a good estimate for when this change occurred.

Finish Options

The 1938 Indestro catalog offered three finish options for the open-end wrenches: triple-plated with polished heads, natural sand-blast, or black enamel with polished faces. And for open-end wrench sets, there was even a fourth option for cadmium plating. The multiplicity of finish options for open-end wrenches means that we won't be able to use the observed finish as a factor in estimating the manufacturing date.

The other wrench types were initially offered in only one standard finish: triple-plated for the long offset, short offset, and angled box wrenches, and "rust proof plating" (probably cadmium) for the open+box wrenches.

By 1941 some of the finish options had changed, as all three types of box-end wrenches now had an option for cadmium plating, and the black enamel finish for open-end wrenches had been discontinued. In addition, the open+box wrenches were listed as triple-plated with polished heads.

It's worth noting that Indestro's early triple-plated finishes often have an appearance more like nickel plating, with a slight yellowish tint rather than the bright silvery-white of later chrome finishes. It may be that the chrome layer of the early finishes was relatively thin, so that after some amount of wear more of the nickel finish was exposed. The examples here that are reported with nickel finishes probably represent original triple-plated finishes after varying amounts of use and wear.

The following sections will look at examples of the various "Select Steel" tool styles: Open+Box, Open-End, Short Angled Box-End, Offset Box-End, and Short Offset Box-End.

Indestro "Select Steel" Open+Box Wrenches

In the early 1930s a type of wrench with open and box ends of different sizes became popular for automobile tool kits. These wrenches were typically sold in sets secured by a bolt and wing nut, with the range of sizes spanning the most common nut sizes. We refer to this style as open+box wrenches.

The open+box wrench style is believed to have originated with the Auto-Kit Brand wrenches produced by J.P. Danielson beginning in the early 1930s. (Auto-Kit wrench sets were being offered by Western Auto Supply as early as 1933.)

Indestro probably started making open+box wrenches around 1936 and eventually became one of the major producers of such wrenches. Indestro's initial design used depressed panels shaped like a truncated triangle, following the tapered contour of the wrench shank. Although the catalogs illustrated this triangular design for a number of years, actual wrenches with this design are quite rare — the two examples here are the only ones we've seen. The scarcity of examples strongly suggests that the open+box wrenches were soon redesigned to use Indestro's trademark "streamlined" panels.

The 1937 catalog listed the open+box wrenches in six models, 901 (5/16x7/16), 902 (7/16x1/2), 903 (1/2x9/16), 904 (9/16x5/8), 905 (5/8x3/4), and 906 (3/4x7/8). (The box-end was always the smaller of the openings.)

We'll begin with two examples of early open+box wrenches, showing both the original triangular panel design and marked with "Alloy Steel" as well.

Early Indestro "Chicago" 5/16x7/16 Open+Box Wrench

Fig. 154. Indestro "Chicago" 5/16x7/16 Open+Box Wrench, with Inset for Back Side, ca. 1936-1938.

Fig. 154 shows a rare early Indestro 5/16x7/16 open+box wrench, marked with "Chicago - U.S.A." forged into the triangular depressed panel, with "Drop Forged Alloy Steel" forged into the back side. The fractional sizes are also forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 4.0 inches, and the finish is plain steel.

The "Alloy Steel" marking indicates production in 1938 or earlier.

This wrench is interesting for its use of depressed panels in a triangular design, indicating relatively early production before the open+box wrenches adopted the well-known streamlined panel design.

Early Indestro "Chicago" 5/8x3/4 Open+Box Wrench

Fig. 155. Indestro Chicago 5/8x3/4 Open+Box Wrench, with Inset for Back Side Detail, ca. 1936-1938.

Fig. 155 shows another early Indestro 5/8x7/8 open+box wrench, marked with "Chicago - U.S.A." forged into the triangular depressed panel, with "Drop Forged Alloy Steel" forged into the opposite side. The fractional sizes are also forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 6.5 inches, and the finish is cadmium plating.

The "Alloy Steel" marking indicates production in 1938 or earlier.

This wrench is interesting for its use of depressed panels in a triangular design, indicating relatively early production before the open+box wrenches adopted the well-known streamlined panel design.

Indestro "Chicago" 5/16x7/16 Open+Box Wrench

Fig. 156. Indestro "Chicago" 5/16x7/16 Open+Box Wrench, with Inset for Back Side, ca. 1939+.

Fig. 156 shows an Indestro 5/16x7/16 open+box wrench, marked with "Indestro" and "Chicago-U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the opposite side. The fractional sizes are forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 4.0 inches, and the finish is chrome plating.

Indestro "Chicago" 9/16x5/8 Open+Box Wrenches

The next two figures show examples of 9/16x5/8 open+box wrenches with different finishes.

Fig. 157. Indestro "Chicago" 9/16x5/8 Open+Box Wrench, with Inset for Back Side, ca. 1939+.

Fig. 157 shows an Indestro 9/16x5/8 open+box wrench, marked with "Indestro" and "Chicago-U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the opposite side. The fractional sizes are forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 5.8 inches, and the finish is chrome plating.

Fig. 158. Indestro "Chicago" 9/16x5/8 Open+Box Wrench, with Inset for Back Side, ca. 1939+.

Fig. 158 shows another example of an Indestro 9/16x5/8 open+box wrench, marked with "Indestro" and "Chicago-U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the opposite side. The fractional sizes are forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 5.8 inches, and the finish is plain steel, with traces of cadmium plating.

Indestro "Chicago" 5/8x3/4 Open+Box Wrench

Fig. 159. Indestro "Chicago" 5/8x3/4 Open+Box Wrench, with Inset for Back Side, ca. 1939+.

Fig. 159 shows an Indestro 5/8x3/4 open+box wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the opposite side. The fractional sizes are forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 6.5 inches, and the finish is plain steel, possibly with traces of cadmium plating.

Indestro "Chicago" 3/4x7/8 Open+Box Wrench

Fig. 160. Indestro "Chicago" 3/4x7/8 Open+Box Wrench, with Inset for Back Side Detail, ca. 1939+.

Fig. 160 shows an Indestro 3/4x7/8 open+box wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side. The fractional sizes are forged into small depressed panels, one within the face of the open end, and the other near the box end.

The overall length is 7.6 inches, and the finish is chrome plating.

Indestro "Select Steel" Open-End Wrenches

The "Select Steel" line offered open-end engineer's wrenches in a wide range of industry-standard sizes, ranging from No. 721 (5/16x3/8) up to No. 741 (1-1/2x1-11/16).

The open-end wrenches were initially offered in several finish options, and the catalogs show model numbers with a prefix (e.g. "P" for triple-plated) to indicate the finish. However, all of the known examples of early production (the Indestro "Chicago" era) are marked only with the industry-standard number, regardless of finish.

Since production of the open-end wrenches began in 1937, examples with an "Alloy Steel" marking should be possible, but none have been found yet.

Indestro "Chicago" No. 721 5/16x3/8 Open-End Wrench

[Indestro Chicago 721 5/16x3/8 Open-End Wrench]

Fig. 161. Indestro "Chicago" No. 721 5/16x3/8 Open-End Wrench, with Inset for Back Side.

Fig. 161 shows an Indestro No. 721 5/16x3/8 open-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side panel.

The overall length is 3.8 inches, and the finish is plain steel.

Indestro "Chicago" No. 25 1/2x19/32 Open-End Wrench

Fig. 162. Indestro Chicago No. 25 1/2x19/32 Open-End Wrench, with Inset for Back Side Detail.

Fig. 162 shows an Indestro 25 1/2x19/32 open-end wrench, marked with "indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 5.5 inches, and the finish is nickel plating.

Indestro "Chicago" No. 729 5/8x3/4 Open-End Wrenches

The next two figures show examples of the Indestro No. 729 wrench, with different finish options.

Fig. 163. Indestro "Chicago" No. 729 5/8x3/4 Open-End Wrench, with Inset for Back Side Detail.

Fig. 163 shows an Indestro No. 729 5/8x3/4 open-end wrench, marked with Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 7.4 inches, and the finish is plain steel.

Fig. 164. Indestro "Chicago" No. 729 5/8x3/4 Open-End Wrench, with Inset for Back Side.

Fig. 164 shows another Indestro No. 729 5/8x3/4 open-end wrench with a different finish, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 7.5 inches, and the finish is chrome or nickel plating.

Indestro "Chicago" No. 29 11/16x25/32 Open-End Wrench

[Indestro Chicago No. 29 11/16x24/32 Open-End Wrench]

Fig. 165. Indestro "Chicago" No. 29 11/16x25/32 Open-End Wrench, with Inset for Back Side, ca. 1937+.

Fig. 165 shows an Indestro No. 29 11/16x25/32 open-end wrench, marked with "indestro" and "Chicago - U.S.A." forged into the streamlined panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 7.4 inches, and the finish is plain steel.

Indestro "Chicago" No. 731 3/4x13/16 Open-End Wrench

Fig. 166. Indestro "Chicago" No. 731 3/4x13/16 Open-End Wrench, with Inset for Back Side Detail.

Fig. 166 shows an Indestro No. 731 3/4x13/16 open-end wrench, marked "indestro" and "Chicago - U.S.A." in the streamlined depressed panel, with "Drop Forged Select Steel" on the back side.

The overall length is 8.5 inches, and the finish is plain steel.

Indestro "Chicago" No. 731-A 3/4x7/8 Open-End Wrench

Fig. 167. Indestro "Chicago" No. 731-A 3/4x7/8 Open-End Wrench, with Inset for Back Side.

Fig. 167 shows an Indestro No. 731-A 3/4x7/8 open-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 8.5 inches, and the finish is plain steel.

Indestro "Chicago" No. 33-B 13/16x15/16 Inch Open-End Wrench

Fig. 168. Indestro "Chicago" No. 33-B 13/16x15/16 Inch Open-End Wrench, with Inset for Back Side.

Fig. 168 shows an Indestro No. 33-B 13/16x15/16 inch open-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 9.3 inches, and the finish is plain steel with traces of cadmium plating.

Indestro "Chicago" No. 733 7/8x1 Inch Open-End Wrench

Fig. 169. Indestro "Chicago" No. 733 7/8x1 Inch Open-End Wrench, with Inset for Back Side.

Fig. 169 shows an Indestro No. 733 7/8x1 inch open-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 9.2 inches, and the finish is nickel plating.

Indestro "Select Steel" Short Angled Box-End Wrenches

Short angled box-end wrenches were one of the initial styles offered in 1937. The design included streamlined depressed panels on both sides with forged-in markings, and the earliest production was marked with "Drop Forged Alloy Steel".

The angled box wrenches were initially available in four models, 921 (3/8x7/16), 922 (1/2x9/16), 923 (5/8x11/16), and 924 (3/4x25/32). The 1938 catalog added two more models, 919 (1/4x5/16), and 925 (13/16x7/8).

The finish for the short box-end wrenches was initially specified as triple-plating, but a cadmium finish option was available by 1941.

Indestro "Chicago" [No. 919] 1/4x5/16 Short Angled Box-End Wrench

Fig. 170. Indestro "Chicago" [No. 919] 1/4x5/16 Box-End Wrench, with Insets for Back Side and Side View, ca. 1939 to Early 1940s.

Fig. 170 shows an Indestro "Chicago" [No. 919] 1/4x5/16 box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 3.6 inches, and the finish is nickel plating.

The "Select Steel" marking indicates production in 1939 or later, and the older plated finish suggests production in the pre-war period.

Indestro "Chicago" [No. 921] 3/8x7/16 Short Angled Box-End Wrenches

The next figures show two generations of the No. 921 wrench.

Fig. 171. Indestro "Chicago" [No. 921] 3/8x7/16 Short Angled Box-End Wrench, with Insets for Back Side and Side View, ca. 1937-1938.

Fig. 171 shows an early Indestro "Chicago" [No. 921] 3/8x7/16 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Alloy Steel" forged into the back side.

The overall length is 4.4 inches, and the finish is chrome plating with a slightly yellowish tint.

The "Alloy Steel" marking indicates production in 1937 or 1938.

Fig. 172. Indestro "Chicago" [No. 921] 3/8x7/16 Short Angled Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 172 shows a later Indestro "Chicago" [No. 921] 3/8x7/16 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 4.4 inches, and the finish is plain steel.

The "Select Steel" marking indicates production in 1939 or later, and the plain finish suggests production during the 1942-1945 wartime years.

Indestro "Chicago" [No. 922] 1/2x9/16 Short Angled Box-End Wrench

Fig. 173. Indestro "Chicago" [No. 922] 1/2x9/16 Short Angled Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1939 to Early 1940s.

Fig. 173 shows an Indestro "Chicago" [No. 922] 1/2x9/16 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 5.3 inches, and the finish is triple-plating with polished ends.

The "Select Steel" marking and plated finish indicates production from 1939 to the early 1940s.

This wrench is part of the Klip Tite 920-03K Wrench Set shown in another figure.

Indestro "Chicago" [No. 923] 5/8x11/16 Short Angled Box-End Wrenches

The next figures show two generations of the [No. 923] 5/8x11/16 short angled box wrenches.

Fig. 174. Indestro "Chicago" [No. 923] 5/8x11/16 Short Angled Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1937-1938.

Fig. 174 shows an early Indestro "Chicago" [No. 923] 5/8x11/16 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Alloy Steel" forged into the back side.

The overall length is 6.2 inches, and the finish is nickel plating.

The "Alloy Steel" marking indicates production in 1937 or 1938.

Fig. 175. Indestro "Chicago" [No. 923] 5/8x11/16 Short Angled Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 175 shows a later Indestro "Chicago" [No. 923] 5/8x11/16 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 6.2 inches, and the finish is plain steel.

The "Select Steel" marking indicates production in 1939 or later, and the plain steel finish suggests production during the 1942-1945 wartime years.

Indestro "Chicago" [No. 925] 13/16x7/8 Short Angled Box-End Wrenches

The next figures show two generations of the [No. 925] 13/16x7/8 short angled box wrenches.

Fig. 176. Indestro "Chicago" [No. 925] 13/16x7/8 Short Angled Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1938.

Fig. 176 shows an early Indestro [No. 925] 13/16x7/8 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Alloy Steel" forged into the back side.

The overall length is 8.3 inches, and the finish is nickel plating.

This wrench model was first available in 1938, which together with the "Alloy Steel" marking indicates production in 1938.

Fig. 177. Indestro "Chicago" [No. 925] 13/16x7/8 Short Angled Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1941.

Fig. 177 shows a slightly later Indestro [No. 925] 13/16x7/8 short angled box-end wrench, marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 8.2 inches, and the finish is heavy cadmium plating.

The heavy cadmium plating on this example suggests production around 1941, when a cadmium finish option was available for box wrenches. (The cadmium plating used as a wartime substitute was generally very thin.)

Indestro "Klip Tite" 920-03K Box-End Wrench Set

Fig. 178. 1938 Catalog Listing for Indestro Klip Tite Wrench Set.

In addition to selling individual wrenches, Indestro offered various sets of wrenches held together in a "Klip Tite" metal holder. An example of a catalog listing for a Klip Tite wrench set can be seen in Fig. 178, a scan from page 11 of the 1938 Indestro catalog.

This type of metal holder was used for sets of box-end and open-end wrenches, but sets of open+box wrenches were secured with a bolt and wingnut, using a hole in the center of the wrench.

This next figure shows an example of a Klip Tite wrench set.

Fig. 179. Indestro "Klip Tite" 920-03K Three-Piece Wrench Set, with Inset for Top View, ca. 1939 to Early 1940s.

Fig. 179 shows an Indestro "Klip Tite" model 920-03K wrench set, consisting of three short angled box-end wrenches in a steel holder with a thumbscrew. The holder is stamped "Klip Tite Set" with the 920-03K model number.

The wrench sizes are 1/4x5/16, 3/8x7/16, and 1/2x9/16. Each wrench is marked with "Indestro" and "Chicago - U.S.A." forged into the streamlined depressed panel, with "Drop Forged Select Steel" forged into the back side.

The overall length is 5.3 inches. The finish is triple-plating with polished ends and a satin finish on the shank.

The "Select Steel" marking and triple-plated finish indicates production from 1939 to the early 1940s.

Indestro "Select Steel" Offset Box-End Wrenches

The "Select Steel" offset box-end wrenches were first offered in 1938. Based on observational data, the initial design included streamlined depressed panels with forged-in markings on both sides, with "Made in U.S.A." plus the fractional sizes on one side, and with "Forged Select Steel" plus the fractional sizes on the back side. The omission of the company name meant that these wrenches were designed for contract production from the beginning.

Although not marked with the company name, these wrenches are still implicitly marked as Indestro production by the streamlined panel design, trademarked in 1937.

The finish for the offset box-end wrenches was initially specified as triple-plating, but a cadmium finish option was available by 1941.

Indestro "Select Steel" 3/8x7/16 Offset Box-End Wrench

Fig. 180. Indestro "Select Steel" 3/8x7/16 Offset Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 180 shows an Indestro "Select Steel" 3/8x7/16 offset box-end wrench, marked with "Made in U.S.A." forged into the streamlined depressed panel, with "Forged Select Steel" forged into the back side.

The overall length is 7.8 inches, and the finish is plain steel.

The catalogs did not offer a plain finish option for the offset box wrenches, so the plain steel finish on this example indicates production during the 1942-1945 wartime period.

This wrench serves to establish the marking style for the "Select Steel" offset box-end wrenches during the wartime period. In the absence of any examples of the Indestro "Chicago" markings for this series, the marking style exhibited here presumably extended back to the initial production in 1938.

Indestro "Select Steel" 1/2x9/16 Offset Box-End Wrench

Fig. 181. Indestro "Select Steel" 1/2x9/16 Offset Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 181 shows an Indestro "Select Steel" 1/2x9/16 offset box-end wrench, marked with "Made in U.S.A." forged into the streamlined depressed panel, with "Forged Select Steel" forged into the back side.

The overall length is 8.7 inches, and the finish is a plain steel.

The catalogs did not offer a plain finish option for the offset box wrenches, so the plain steel finish on this example indicates production during the 1942-1945 wartime period.

Indestro "Select Steel" 5/8x11/16 Offset Box-End Wrench

Fig. 182. Indestro "Select Steel" 5/8x11/16 Offset Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1938-1941.

Fig. 182 shows an Indestro "Select Steel" 5/8x11/16 offset box-end wrench, marked with "Made in U.S.A." forged into the streamlined depressed panel, with "Forged Select Steel" forged into the back side.

The overall length is 10.0 inches, and the finish is a thin chrome plating with a slightly yellowish tint.

This example is believed to be representative of the pre-war "Select Steel" offset box wrenches.

Indestro "Select Steel" 13/16x7/8 Offset Box-End Wrench

Fig. 183. Indestro "Select Steel" 13/16x7/8 Offset Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 183 shows an Indestro "Select Steel" 13/16x7/8 offset box-end wrench, marked with "Made in U.S.A." and the fractional sizes forged into the front panel, with "Forged Select Steel" and the fractional sizes forged into the back side panel.

The overall length is 12.9 inches, and the finish is plain steel.

The plain finish suggests production during the wartime period.

Indestro "Select Steel" 1-1/16x1-1/8 Offset Box Wrench

[Indestro Select Steel No. 917 1-1/16x1-1/8 Offset Box Wrench]

Fig. 184. Indestro "Select Steel" 1-1/16x1-1/8 Offset Box Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 184 shows an Indestro "Select Steel" 1-1/16x1-1/8 offset box wrench, marked with "Made in U.S.A." and the fractional sizes forged into the front panel, with "Forged Select Steel" and the fractional sizes forged into the back side panel.

The overall length is 16.2 inches, and the finish is plain steel.

The 1-1/16x1-1/8 offset box wrench was listed as model No. 917 in the 1941 Indestro catalog, at which time a triple-plated finish was standard. The plain finish of this example suggests production during the wartime period.

Indestro "Select Steel" Short Offset Box-End Wrenches

The "Select Steel" short offset box-end wrenches were first offered in 1938. Based on observational data, the initial design included streamlined depressed panels with forged-in markings on both sides, with "Made in U.S.A." plus the fractional sizes on one side, and with "Forged Select Steel" on the back side. The omission of the company name meant that these wrenches were designed for contract production from the beginning.

Although not marked with the company name, these wrenches are still implicitly marked as Indestro production by the streamlined panel design, trademarked in 1937.

The finish for the offset box-end wrenches was initially specified as triple-plating, but a cadmium finish option was available by 1941.

Indestro "Select Steel" [No. 933] 5/8x11/16 Short Offset Box-End Wrench

Fig. 185. Indestro "Select Steel" [No. 933] 5/8x11/16 Short Offset Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1938-1941.

Fig. 185 shows an Indestro "Select Steel" [No. 933] 5/8x11/16 short offset box-end wrench, marked with "Made in U.S.A." and the fractional sizes forged into the streamlined depressed panel, with "Forged Select Steel" forged into the back side.

The overall length is 6.1 inches, and the finish is chrome plating with a slightly yellowish tint.

This example is believed to be representative of the pre-war "Select Steel" short offset box wrenches.

Early Tools and the Economy Line

Indestro Stamped-Steel Tools

Early Indestro Nut and Tap Wrench Set

Indestro Nut and Tap Wrench Set

Indestro 141 1/2x9/16 Box-End Wrench

Indestro 142 5/8x11/16 Box-End Wrench

Indestro 144 13/16x7/8 Box-End Wrench

Indestro 6 Inch Slip-Joint Thin Combination Pliers

Automotive Service Tools

Indestro [No. 619] 9/16x3/4 Socket Wrench

Indestro 1/2x9/16 Socket Wrench

Duro Metal Products 621 3/4x7/8 Socket Wrench

Duro Metal Products 624 13/16x13/16 Socket and Box-End Wrench

Duro Metal Products 634 (1/2x9/16)x(5/8x11/16) Socket Wrench

Duro Metal Products 600 1/2x9/16 Socket Wrench

Duro Metal Products 631 (1/2x5/8)x1/2 Triple Socket Wrench

[Duro Metal Products] 633 (1/2x5/8)x5/8 Triple Socket Wrench

Duro Metal Products 615 21/32 Socket Wrench

[Duro] "Chromium Vanadium" 617 9/16 Socket Wrench

Duro Metal Products [0626] 3/4 Speeder Socket (Rim) Wrench

Duro Metal Products 671 11/16 Ratcheting Box Wrench

Duro Metal Products No. 2116 Battery Pliers

Indestro No. 410 Universal Drain Plug Wrench

Duro No. 412 Reciprocating Valve Grinder

Indestro 2021-V8 Valve Guide Punch

Hex-Drive Socket Sets

Indestro [No. 19] 1/2-Hex Drive Socket Set

Indestro No. 19 Socket Set in Partially Opened Position

Indestro 1/2-Hex Drive Sockets from No. 19 Set

Indestro No. 28 1/2-Hex Drive Socket Set

Indestro No. 28 Socket Set in Partially Opened Position

Indestro 1/2-Hex Drive Ratchet from No. 28 Socket Set

Indestro No. 220 1/2-Hex Drive Socket Set

Indestro 1/2-Hex Drive Sockets from No. 220 Set

Duro Metal Products LTX316 1/2-Hex Drive 16-Piece Socket Set

Duro 1/2-Hex Drive L-T Handle from LTX316 Set in Tee-Handle Position

Duro 1/2-Hex Drive Sockets from LTX316 Set

Duro Metal Products 1/2-Hex Drive 16-Piece Socket Set

Duro No. 673 1/2-Hex Drive Ratchet from 16-Piece Set

Duro 1/2-Hex Drive Sockets from 16-Piece Set

Duro No. 500XX 1/2-Hex Drive Double-Hex Socket Set

Duro 673 1/2-Hex Drive Ratchet

Indestro No. 1236 1/2-Hex Drive Double-Hex Socket Set

Indestro No. 2104 3/8-Hex Drive Socket Set

Indestro No. 350 1/4-Hex Drive Socket Sets

Indestro Super No. 360 1/4-Hex Drive 6-Piece Handle and Socket Set

Square-Drive Socket Sets

Indestro 1/2-Drive Hex Sockets

Early Indestro 1/2-Drive 13-Piece Socket Set

Indestro 1/2-Drive Lever-Action Ratchet from 13-Piece Set

Indestro 1/2-Drive T-L Handle from 13-Piece Set in Ell-Handle Position

Indestro 1/2-Drive T-L Handle in Tee-Handle Position

Indestro 1/2-Drive 6-Point Sockets from 13-Piece Set

Early Duro Metal Products "Double Guarantee" 1/2-Drive Socket Set

Duro No. 660 1/2-Drive L-T Convertible Handle from "Double Guarantee" Socket Set

Duro No. 660 1/2-Drive L-T Convertible Handle in Ell-Handle Position

Duro No. 672 1/2-Drive Ratchet from "Double Guarantee" Socket Set

Duro 1/2-Drive 8 Inch Double-Male Extension from "Double Guarantee" Socket Set

Duro 1/2-Drive Large Sockets from "Double Guarantee" Socket Set

Duro 1/2-Drive Medium Sockets from "Double Guarantee" Socket Set

Early Duro Metal Products 1/2-Drive 23-Piece 6-Point Socket Set

Duro 1/2-Drive No. 660 L-T Convertible Handle from 23-Piece Socket Set

Duro 1/2-Drive large Sockets from 23-Piece Socket Set

Early Duro No. 825 1/2-Drive 25-Piece Garage Socket Wrench Set

Duro 652 1/2-Drive Short Speeder from No. 825 Set

Duro 1/2-Drive Sockets from No. 825 Socket Set

Duro-Bilt 1/2-Drive 20-Piece Socket Set [Duro No. 820FA]

Duro 1/2-Drive Screwdriver Socket from "20-Piece" Socket Set

Duro-Bilt 1/2-Drive 36-Piece Socket Set

Early 12-point Socket Sets

Indestro "Chromium Vanadium" 1/2-Drive Double-Hex Sockets from 17-Piece Socket Set

Indestro No. 1513 1/2-Drive 13-Piece Double-Hex Socket Set

Indestro [No. 659] 1/2-Drive Male-Female Sliding Tee Handle from No. 1513 Set

Indestro 1/2-Drive Double-Hex Sockets from No. 1513 Set

Indestro No. 1518 1/2-Drive 18-Piece Double-Hex Socket Set

[Indestro No. 655] 1/2-Drive Lever-Action Ratchet from No. 1518 Set

Indestro [No. 641] 1/2-Drive Ell Handle from No. 1518 Set

Indestro 1/2-Drive Double-Hex Sockets from No. 1518 Set

Indestro No. 1536 1/2-Drive 12-Point Socket Set

Indestro 1/2-Drive 13 Inch Speeder