Alloy Artifacts  

Diamond Calk Horseshoe Company

Table of Contents

Introduction


Company History

The Diamond Calk Horseshoe Company was founded in 1908 by Otto Swanstrom, a blacksmith operating in Duluth, Minnesota. As the name suggests, the company was formed to make calks and horseshoes, and their initial product was a patented insertable calk for horseshoes. (A calk is a gripping bit on a horseshoe, added for better traction on ice or slippery surfaces.) In 1910 the company built a factory at 4630 West Third Street in Duluth.

Diamond was very successful in their calk and horseshoe business, but as the tractor and automobile reduced the need for horses and horseshoes, the company turned its forging skills to the production of adjustable wrenches.

By 1921 Diamond Calk had become a prosperous business employing 150 workers and producing drop-forged railroad supplies and wrenches, in addition to their line of calks and horseshoes.

[1922 Advertisement for Diamond Adjustable Wrenches]
Fig. 1. 1922 Advertisement for Diamond Adjustable Wrenches. [External Link]

Fig. 1 shows an example of an early Diamond adjustable wrench, published as part of an advertisement on page 23 of the April, 1922 issue of The Horseshoer's Magazine.

By 1924 Diamond adjustable wrenches were available in sizes from 4 to 18 inches for single-ended and 4 to 12 inches for double-ended models, and with several finish options including nickel plating.

[1924 Advertisement for Diamond Adjustable Wrenches]
Fig. 2. 1924 Advertisement for Diamond Adjustable Wrenches. [External Link]

Fig. 2 shows an ad for Diamond adjustable wrenches on a display board, as published on page 74 of the December, 1924 edition of The American Exporter.


Supplier to Motor Tool Specialty Company

In the mid 1920s Diamond was selected as the supplier of adjustable wrenches for the Motor Tool Specialty Company, the distributor organization for the Snap-On Wrench Company. This must have been both a high honor and a tremendous boost for their sales efforts, as Diamond brand wrenches were shown together with the Snap-On sockets and drive tools.

Snap-On continued to offer Diamond brand wrenches in its catalogs until the late 1930s, and when its own Blue Point brand adjustable wrenches were introduced, Diamond appears to have continued as the contract manufacturer.

Some time after the success of its adjustable wrenches, Diamond expanded its product line to include various styles of pliers, cutters, tin snips, auto (monkey) wrenches, and other tools.

"Diamalloy" Alloy Steel

In 1931 Diamond began using alloy steel for its adjustable wrenches, for which it later registered the "Diamalloy" trademark.

[1935 Ad for the Diamond Calk Horseshoe Company]
Fig. 2B. 1935 Ad for the Diamond Calk Horseshoe Company.

The scan in Fig. 2B shows an ad for Diamond tools, as published on page 50 of the September 26, 1935 edition of Hardware Age.

The illustration shows Diamalloy adjustable wrenches, slip-joint combination pliers, fencing pliers, pitching horseshoes, and other forged tools.

The description of the adjustable wrenches notes the alloy steel construction, and a close look at the illustration shows that the wrench is marked "Forged Diamalloy Steel".

The fencing pliers are believed to be the first fixed-pivot pliers offered by the company.

The text also notes the availability of a new catalog, but no copy is known so far.

By 1941 Diamond was offering Diamalloy diagonal cutters as well.


Groove-Joint Pliers

In late 1951 Diamond began offering tongue-and-groove pliers under the "Groove-Joint" brand name. These pliers were made with the ribs forged directly into the handles and were based on the 1952 Daugherty patent 2,622,464, licensed from Utica Drop Forge & Tool.

Diamond was an early licensee of the Utica patent and was already offering Groove-Joint pliers before the patent was issued. Some (presumably early) production of the pliers was marked "Licensed".

An example of the new tongue-and-groove pliers can be seen in an advertisement on page 307 [External Link] of the October 1959 issue of Popular Mechanics.

Groove-Joint pliers became an important part of the company's contract production, and Diamond is known to have supplied the pliers to Snap-on and Duro/Indestro.


A Name Change

In 1958 the company changed its name to Diamond Tool and Horseshoe, dropping the reference to calks, and tools produced after this were marked with the new company name. The date of the change is based on the earliest published reference found, but in any event the advertisement cited in the previous paragraph confirms that the new name was being used by 1959.

The company name change was not significant in terms of tool production, but it does provide us with a benchmark for estimating production dates.


Later Operations

Diamond Tool remained a family-owned business until 1981, when it was sold to the Triangle Corporation, the parent company of the combined Utica, Herbrand, and Bonney tool companies.

Triangle itself was later acquired by Cooper Industries, the corporate parent to numerous other tool companies. Cooper Tools had also acquired the Crescent Niagara Corporation, the parent of Crescent Tools, and over time the production of Diamond adjustable wrenches was merged with the Crescent production.


Patents

Diamond Calk Horseshoe Company: Issued and Licensed Patents
Patent No.InventorFiledIssuedNotes and Examples
1,320,828 G.E. Lindberg02/19/191511/04/1919 Horseshoe with Removable Calks
1,688,601 A.R. Swanstrom12/20/192310/23/1928 Horseshoe
1,850,816 A.R. Swanstrom02/26/193103/22/1932Pitching Horseshoe
1,862,499 A.R. Swanstrom11/19/193006/07/1932Horseshoe Calk
2,622,464 W.V. Daugherty12/07/195112/23/1952 Method of Forging Tongue-and-Groove Pliers
Patent licensed from Utica
2,818,758 J.E. Swanstrom et al03/27/195601/07/1958 Spring-Loaded Pliers
2,849,908 J.E. Swanstrom et al08/06/195709/02/1958 Adjustable Wrench with Locking Mechanism
3,304,817 J.E. Swanstrom et al02/26/196502/21/1967 Chain Pipe Wrench
3,404,457 J.E. Swanstrom, Sr.07/26/196610/08/1968 Alloy Rivet for Pliers ("Copaloy")
3,739,664 J.E. Swanstrom et al10/14/197106/19/1973 Forging Method
H18P Pliers
H112P Pliers

Trademarks

Diamond registered several trademarks, initially for their distinctive Diamond-Horseshoe logo, filed in 1921 with the first use listed as 1908. A later registration added the logo showing "DIAMOND" in a diamond shape, filed in 1925 with the first use listed as 1919. Their well-known "Diamalloy" trademark for alloy steel tools listed a first use in 1931.

In late 1951 Diamond began using the "Groove-Joint" brand for a line of tongue-and-groove pliers, and the trademark registration was filed in 1963. (By this time the company name had changed to "Diamond Tool and Horseshoe".)

Diamond Calk Horseshoe: Registered Trademarks
Text Mark or Logo Reg. No. First Use Date Filed Date Issued Notes
Diamond Horseshoe with Calk 168,676 08/01/1908 03/11/1921 05/29/1923 Horseshoe and diamond with calk in the center.
Serial 144,607. Published February 27, 1923.
Renewed in 1943.
Diamond Logo 209,074 1919 10/24/1925 02/16/1926 Diamond logo.
Serial 222,226. Published December 8, 1925.
Renewed in 1946
Diamalloy [Diamond Logo] 401,456 Late 1931 12/14/1942 05/18/1943  
Diamalloy [Diamond Logo] 585,695 Late 1931 09/08/1952 02/16/1954 Used for tinner's snips and heavy-duty nippers
Groove-Joint 772,762 06/04/1952 02/04/1963 07/07/1964 Tongue-and-Groove Pliers
Earliest known use in catalog W17 dated October, 1951.

Tool Identification

Diamond's production for its own brands was generally clearly marked with the company name, but contract production may be difficult to identify.

Diamond-Horseshoe Logo

[Diamond-Horseshoe Logo]
Fig. 3. Diamond-Horseshoe Logo from Trademark #168,676.

The scan in Fig. 3 shows the Diamond-Horseshoe logo as it was presented for trademark #168,676.

This logo was frequently forged into the shank of Diamond adjustable wrenches, and may be marked on other tools as well.


Manufacturing Dates

Diamond tools are not known to be marked with a date code, so the estimation of manufacturing dates must be made based on other factors. The following list of observations may be helpful in estimating the manufacturing date for some tools.


References and Resources

Photographs and observations of particular tools are based on items in the Alloy Artifacts collection.

A biography of Otto Swanstrom can be found on page 786 of Duluth and St. Louis County, Minnesota [External Link], published in 1921 by the American Historical Society. This reference provides some interesting information about the company at that time.


Catalog Coverage

Diamond catalogs prior to 1940 appear to be extremely rare, and it may be that the company relied primarily on distributors during its earlier years. The lack of catalogs makes it difficult to track the company's product development during this period.

The 1949 catalog supplement lists adjustable and auto wrenches, pliers and cutters, metal cutting snips, and crate opening tools. Included in the pliers section is a DH16 "Diamalloy Handiman" combination tool.

Diamond Calk Horseshoe: Catalog Resources
Catalog Title Year Notes
      N/A (1935):
N/A   1935 No copy known, mentioned in 1935 ad in Hardware Age.
      Supplement 3 (1946?):
Supplement 3 Condensed Catalog 1946? No copyright, undated. 4 pages.
Updates sections W12 and 14.
Notes tools "in production in early post war program."
Available for Download [External Link] from ITCL.
Lists Diamalloy single- and double-ended adjustable wrenches.
Lists Diamalloy pliers in various styles.
Lists Diamalloy diagonal cutters in 4, 5, and 6 inch sizes.
Lists Diamalloy linemen's pliers in 6 and 8 inch sizes.
      Supplement 8 (1949):
Supplement 8 Condensed Catalog 1949 No copyright, dated August 1, 1949. 4 pages.
Updates sections W15 and G45.
Came with price list No. 307-D.
Available for Download [External Link] from ITCL.
Lists Diamalloy single- and double-ended adjustable wrenches.
Diamalloy adjustable wrenches with ring around hanging hole.
      No. 307-D (1949):
No. 307-D Dealers Net Price List 1949 No copyright, dated August 1, 1949.
Available for Download [External Link] from ITCL.
      W17 (1951):
W17 Diamond Wrenches Pliers Tools 1951 No copyright, dated October 1, 1951. 16 pages.
Available for Download [External Link] from ITCL.
Lists monkey and auto wrenches.
Lists HL19½ "Groove-Joint" pliers, earliest known listing.
      W28 (1969):
W28 Diamond Tool and Horseshoe Co. 1969 No copyright, dated March 1, 1969. 24 pages.
Includes price list dated September 1, 1969.
Available for Download [External Link] from ITCL.
Lists Groove-Joint pliers in sizes 4 to 20 inches.
Extensive selection of slip-joint and fixed-joint pliers.
Lists pitching horseshoes.
      W30 (1973):
W30 Diamond Tool and Horseshoe Co. 1973 No copyright, dated January 1, 1973. 28 pages.
Available for Download [External Link] from ITCL.
      H-19 (1973):
H-19 Horseshoes and Farrier Tools 1973 No copyright, dated April 1, 1973.
Available for Download [External Link] from ITCL.
      W-35 (1983):
W-35 Diamond Tool and Horseshoe Co. 1983 No copyright, dated June 1983 on cover. 52 pages.
Available for Download [External Link] from ITCL.
      W-83 (1983):
W-83 Diamond 1983 Subsidiary of Triangle Tool.
      No. 700 (1986):
No. 700 Diamond 1986 Subsidiary of Triangle Tool.

Industrial Distributors and Retail Stores

Diamond tools were carried by a number of industrial distributors and by some large retailers, including Western Auto Supply and the Gamble Stores chain.


Calk Wrenches

Diamond's early tool production was intended for the farrier's trade and included items such as calk wrenches, as well as horseshoes and calks.


Early Diamond 9/16 Calk Wrench

[Early Diamond 9/16 Calk Wrench]
Fig. 4. Early Diamond 9/16 Calk Wrench, with Inset for Back Side Detail, ca. 1919 to Mid 1920s.

Fig. 4 shows an early Diamond calk wrench for sizes 9/16 and 5/8, marked with the "Diamond" logo and Diamond-Horseshoe logo forged into the shank, with "Diamond Calk Horse Shoe Co." and "Duluth, Minn. U.S.A." forged into the back side. The wrench is also marked with the sizes as "5-8 9-16" on both sides.

The overall length is 8.6 inches, and the finish is plain steel.

The wrench opening was measured at 0.58 inches, a nominal 9/16 with normal clearance.

The use of the "Diamond" logo ("Diamond" text in a diamond outline) indicates production in 1919 or later, based on the first use date of this trademark.


Early Tools

By the early 1920s Diamond had begun shifting its production away from the farrier's trade and towards the rapidly-growing automotive market. Not much is known about this part of the company's history due to a lack of catalog coverage, but their early tools included adjustable wrenches as well as tools for automotive service.

[1926 Ad for Diamond Wrenches]
Fig. 5A. 1926 Ad for Diamond Wrenches. [External Link]

Fig. 5A shows a 1926 ad for Diamond wrenches, as published on page 102 of the December, 1926 issue of the Hardware Dealers' Magazine.

The illustration shows double-ended and single-ended adjustable wrenches, plus a spark plug and head bolt wrench. This is currently our only published reference to the latter tool.


Diamond 5/8x15/16 Spark Plug and Head Bolt Wrench

[Diamond 5/8x15/16 Spark Plug and Head Bolt Wrench]
Fig. 5B. Diamond 5/8x15/16 Spark Plug and Head Bolt Wrench, with Insets for Side View and Marking Detail, ca. Mid 1920s.

Fig. 5B shows an early Diamond 5/8x15/16 spark plug and head bolt wrench, a popular tool for Model T service.

The tool is marked with "Diamond Drop-Forged" and "Duluth U.S.A." forged into the shank, as seen in the middle inset.

The overall length is 10.1 inches, and the finish is black paint.

Diamond's version of the popular spark plug and head bolt wrench included a bonus, a 3/4 hexagonal opening near the open end.


"Tool Steel" Adjustable Wrenches

Diamond's original adjustable wrenches from the 1920s were marked "Tool-Steel Drop-Forged" (or equivalent), which was likely a high-carbon steel. In this section we'll explore the company's line of "Tool Steel" wrenches.

After the introduction of "Diamalloy" brand alloy steel tools in 1931, Diamond continued to offer its tool-steel models as a lower cost alternative, and these remained available until at least the 1960s.


Early Adjustable Wrenches


Adjustable Wrench Sizes

Our earliest catalog reference for Diamond adjustable wrenches is the 1927 Snap-on catalog, which offered the (single-ended) wrenches in 4, 6, 8, 10, 12, 15, and 18 inch sizes.

In 1949 the Diamond price list 307-D offered Diamalloy single-ended wrenches in sizes 4, 6, 8, 10, 12, 15, 18, and 24 inches. Double-ended wrenches were listed in 4-6, 6-8, 8-10, and 10-12 inch sizes. At this time the tool-steel wrenches were available only in the single-ended style, and with a reduced number of sizes, listed as 4, 6, 8, 10, and 12 inches.

Characteristics of Early Adjustable Wrenches

After reviewing a large number of Diamond adjustable wrenches, several examples of relatively early production (based on the plain hanging hole) were found to have a consistent set of construction and marking differences, when compared with the more modern wrench production. Based on this review, several features of the construction and markings can be presumed to represent Diamond's earliest wrench production.

One of these details is the presence of a partial ridge on the edges of the handle, left by the trimming die and only partially ground down by later finishing. Later wrench production provided smoothly ground edges on the handle.

Of the marking details, the use of a location marking as "Duluth Minn. U.S.A." appears only on wrenches with other characteristics of early production. Later Diamond wrenches marked the location as "Duluth Minn." with a separate "Made in U.S.A." marking. The wrenches with the "Duluth Minn. U.S.A." marking also mark the company name using "Horse Shoe" as two words, rather than the single word appearing on later production.

Another marking detail found on a few early wrenches is the presence of a forged-in code on the head, in the form of an "A" followed by three numbers. The meaning is unclear, but it could be a date code or an identifier for the forging die.

The next several figures will show examples believed to represent the earliest production of Diamond adjustable wrenches, likely from the early to mid 1920s.


Early "Tool Steel" 6 Inch Adjustable Wrenches

[Diamond Tool Steel 6 Inch Adjustable Wrench]
Fig. 6. Diamond "Tool Steel" 6 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early to Mid 1920s.

Fig. 6 shows an early Diamond 6 inch adjustable wrench, marked "Diamond" and "Tool-Steel Drop-Forged" with the Diamond-Horseshoe logo forged into the shank, with "Diamond Calk Horse Shoe Co." and "Duluth, Minn. U.S.A." forged into the back side. The wrench is also marked with a forged-in code "A215" near the adjusting knurl.

The overall length is 6.2 inches, and the maximum opening is 0.7 inches. The head thickness was measured at 0.47 inches.

The finish is plain steel.

The Alloy Artifacts collection includes another wrench very similar to this one, but with a forged-in code "A216".


[Diamond Tool Steel 6 Inch Adjustable Wrench]
Fig. 7. Diamond "Tool Steel" 6 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early to Mid 1920s.

Fig. 7 shows another similar early Diamond 6 inch adjustable wrench, marked "Diamond" and "Tool-Steel Drop-Forged" with the Diamond-Horseshoe logo forged into the shank, with "Diamond Calk Horse Shoe Co." and "Duluth, Minn. U.S.A." forged into the back side. The wrench is also marked with a forged-in code "A221" near the adjusting knurl.

The overall length is 6.2 inches, and the maximum opening is 0.7 inches. The head thickness was measured at 0.51 inches.

The finish is plain steel.

The Alloy Artifacts collection includes two other 6 inch wrenches very similar to the examples shown here, but with forged-in codes "A216" and "A248".


Early "Tool Steel" 8 Inch Adjustable Wrenches

[Diamond Tool Steel 8 Inch Adjustable Wrench]
Fig. 8. Diamond "Tool Steel" 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early to Mid 1920s.

Fig. 8 shows an early Diamond 8 inch adjustable wrench, marked "Diamond" and "Tool-Steel Drop-Forged" with the Diamond-Horseshoe logo forged into the shank, with "Diamond Calk Horse Shoe Co." and "Duluth, Minn. U.S.A." forged into the back side. The wrench is also marked with a forged-in code "A330" near the adjusting knurl.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.58 inches.

The finish is plain steel.

[Diamond Tool Steel 8 Inch Adjustable Wrench]
Fig. 9. Diamond "Tool Steel" 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early to Mid 1920s.

Fig. 9 shows another early Diamond 8 inch adjustable wrench, marked "Diamond" and "Tool-Steel Drop-Forged" with the Diamond-Horseshoe logo forged into the shank, with "Diamond Calk Horse Shoe Co." and "Duluth, Minn. U.S.A." forged into the back side. The wrench is also marked with a forged-in code "A333" near the adjusting knurl.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.59 inches.

The finish is plain steel with a thin lacquer coating remaining on the handle.


Early "Tool Steel" 12 Inch Adjustable Wrench

[Diamond Tool Steel 12 Inch Adjustable Wrench]
Fig. 10. Diamond "Tool Steel" 12 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Mid to Late 1920s.

Fig. 10 shows an early Diamond 12 inch adjustable wrench, marked "Diamond" and "Tool-Steel Drop-Forged" with the Diamond-Horseshoe logo forged into the shank, with "Diamond Calk Horse Shoe Co." and "Duluth, Minn. U.S.A." forged into the back side.

The overall length is 12.3 inches, and the maximum opening is 1.5 inches. The head thickness was measured at 0.85 inches.

The finish is plain steel.

This example lacks the forged-in code and has smoothly ground edges, suggesting a somewhat later production date.


Plain Hanging Holes

Earlier adjustable wrenches can be recognized by the plain hanging hole.


"Tool Steel" 4 Inch Adjustable Wrench

[Diamond Tool Steel 4 Inch Adjustable Wrench]
Fig. 11. Diamond "Tool Steel" 4 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. Late 1920s to 1930s.

Fig. 11 shows a Diamond adjustable wrench in the ever-popular 4 inch size, marked "Diamond Calk Horseshoe Co." and "Duluth, Minn." with the Diamond-Horseshoe logo, a registered trademark of the company. The back side markings show "Diamond" in a diamond-shaped logo, with "Tool-Steel", "Drop-Forged", and "Made in U.S.A." at the end.

The overall length is 4.4 inches, and the maximum opening is 0.5 inches.

The finish is worn to reveal a copper plating underneath, and may be either nickel or chrome on top.

This example has the early version of the Diamond-Horseshoe logo, and if you look carefully at the logo, you can see that the diamond has a calk in the center.

Another detail to note is that the hanging hole does not have a reinforcing ring around it. The illustrations in the Snap-On catalogs from 1927 through 1939 for Diamond (and later Diamalloy) wrenches show this type of plain hole. By 1948 the Blue-Point wrenches, still made by Diamond, are illustrated with a ring around the hole.


"Tool Steel" 8 Inch Adjustable Wrench

[Diamond Tool Steel 8 Inch Adjustable Wrench]
Fig. 12. Diamond "Tool Steel" 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early 1930s.

Fig. 12 shows a Diamond 8 inch adjustable wrench, marked with the Diamond logo plus "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

The overall length is 8.1 inches, and the maximum opening is 0.9 inches. The head thickness was measured at 0.59 inches. The finish is plain steel.

The markings on this wrench follow the later conventions, with "Made in U.S.A." on the side with the Diamond logo and "Duluth, Minn." on the back side. Despite the later markings though, the finish is still somewhat rough, with a ridge from the trimming operation still visible on the handle edges. The finish suggests a relatively early production date, probably in the early 1930s.


"Tool Steel" 10 Inch Adjustable Wrenches

The next two figures show examples of "Tool Steel" wrenches in the 10 inch size, with differences in the finish.

[Diamond Tool Steel 10 Inch Adjustable Wrench]
Fig. 13. Diamond "Tool Steel" 10 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1930s.

Fig. 13 shows a Diamond 10 inch adjustable wrench, marked with the Diamond logo plus "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

The overall length is 10.0 inches, and the maximum opening is 1.1 inches. The head thickness was measured at 0.71 inches.

The finish is plain steel. (The red paint highlighting was probably added by a former owner.)

This example has smoothly ground edges and a "Made in U.S.A." marking, suggesting a later production date than the earliest examples in the previous section. The plain hanging hole suggests production prior to the 1940s.

[Diamond Tool Steel 10 Inch Adjustable Wrench]
Fig. 14. Diamond "Tool Steel" 10 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1930s.

Fig. 14 shows a similar Diamond 10 inch adjustable wrench, marked with the Diamond logo plus "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

The overall length is 10.0 inches, and the maximum opening is 1.1 inches. The head thickness was measured at 0.73 inches.

The finish is chrome plating.

The plain hanging hole suggests production prior to the 1940s.


Broached Hanging Holes

By 1940 Diamond was offering a new feature for its adjustable wrenches: a double-hex broached hanging hole. The broached hole obviously required having a ring of material around the hanging hole, so Diamond redesigned its wrenches with a reinforced ring thick enough to allow the double-hex broaching.

The broached hole was available for both the tool-steel and alloy (Diamalloy) models, but it's not known whether the new feature was present on all wrench models, or just as an optional feature. For now we are assuming that it was optional, so that wrenches with broached holes and with reinforced but unbroached holes went into production around the same time.

Currently we're unsure of when the broached-hole feature was first offered by Diamond. Our only catalog reference to Diamond production with broached hanging holes is from a 1940 Gamble's Auto Supply catalog, which offered Diamond-made wrenches under the Gamble's and Tiger (alloy) brands. The Diamond wrenches illustrated in the Snap-On catalogs from 1927 through 1939 show a plain hanging hole, and a Diamond catalog from the late 1940s shows a reinforced (but not broached) hanging hole. Hopefully we'll be able to find a Diamond catalog from around 1940 to help resolve the questions.

The only other manufacturer known to have offered adjustable wrenches with a broached hole was the J.P. Danielson Company, and its "Bet'R-Grip" brand wrenches were available with this feature from 1933 through 1947.

The next few figures will show examples of Diamond wrenches with broached hanging holes.


Tool Steel 6 Inch Adjustable Wrench with Broached Opening

[Diamond 6 Inch Adjustable Wrench]
Fig. 15. Diamond 6 Inch Adjustable Wrench, with Insets for Side View and Marking Detail, ca. 1940 to Late 1940s.

Fig. 15 shows a Diamond 6 inch adjustable wrench with a broached hanging hole, marked with the Diamond logo, "Tool-Steel Drop-Forged", and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side.

Both sides are also marked with the nominal size as "6" followed by a double-quote inch mark, and the hole is marked with its "1/2" size. Note that this wrench is not marked with the Diamond-Horseshoe logo, possibly due to insufficient space.

The overall length is 6.3 inches, and the maximum opening is 0.8 inches. The head thickness was measured at 0.46 inches.

The finish is plain steel.

The distinctive feature of this example is the 1/2 inch double-hex broached hanging hole, a feature also seen on J.P. Danielson "Bet'R-Grip" wrenches from the 1930s.


Tool Steel 8 Inch Adjustable Wrench with Broached Opening

[Diamond 8 Inch Adjustable Wrench]
Fig. 16. Diamond 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early 1940s.

Fig. 16 shows a Diamond 8 inch adjustable wrench with a broached hanging hole. The wrench is marked with the Diamond logo followed by "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side.

Both sides are also marked with the "8 In." nominal size, and the hole is marked with its "9/16" size.

The overall length is 8.1 inches, and the maximum opening is 0.9 inches. The head thickness was measured at 0.56 inches.

The finish is chrome plating.


Tool Steel 10 Inch Adjustable Wrench with Broached Opening

[Diamond 8 Inch Adjustable Wrench]
Fig. 17. Diamond 10 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 17 shows a Diamond 10 inch adjustable wrench with a broached hanging hole. The wrench is marked with the Diamond logo followed by "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side.

Both sides are also marked with the "10 In." nominal size, and the hole is marked with its "5/8" size.

The overall length is 10.2 inches, and the maximum opening is 1.2 inches. The head thickness was measured at 0.69 inches.

The finish is cadmium plating, with some areas showing the copper underplating.

The cadmium finish suggests production during the 1942-1945 wartime years.


Reinforced Hanging Holes

Broached hanging holes were discontinued sometime in the mid to late 1940s, but definitely by the time of the 1948 catalog. After discontinuing the broached hanging holes, Diamond retained the ridge or reinforcing ring around the hanging hole.


Later "Tool Steel" 6 Inch Adjustable Wrench

This next figure shows a later example of the Tool-Steel line, recognized by the ring around the hanging hole.

[Diamond 6 Inch Adjustable Wrench]
Fig. 18. Diamond "Tool Steel" 6Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940s to 1958.

Fig. 18 shows a later Diamond 6 inch adjustable wrench, marked with the Diamond logo plus "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

The overall length is 6.2 inches, and the maximum opening is 0.8 inches.

The finish is plain steel, with extensive pitting due to rust.

The reinforced hanging hole suggests production in the 1940s or later, and the use of the earlier company name indicates production in 1958 or earlier.


Later "Tool Steel" 12 Inch Adjustable Wrench

[Diamond 12 Inch Adjustable Wrench]
Fig. 19. Diamond "Tool Steel" 12 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940s to 1958.

Fig. 19 shows a later Diamond 12 inch adjustable wrench, marked with the Diamond logo plus "Tool-Steel Drop-Forged" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

The overall length is 12.2 inches, and the maximum opening is 1.3 inches. The head thickness was measured at 0.79 inches.

The finish is plain steel.

The reinforced hanging hole suggests production in the 1940s or later, and the use of the earlier company name indicates production in 1958 or earlier.


Diamalloy Adjustable Wrenches

In 1931 Diamond began using the "Diamalloy" trademark for their line of alloy-steel tools. The trademark was registered in 1942.


Plain Hanging Holes

The earlier Diamalloy adjustable wrenches can be recognized by a plain hanging hole, in keeping with their "Tool-Steel" counterparts.

[1935 Catalog Listing for Diamalloy Adjustable Wrenches]
Fig. 20. 1935 Catalog Listing for Diamalloy Adjustable Wrenches.

The scan in Fig. 20 shows a catalog listing for Diamond Diamalloy wrenches, as published on page 59 of the Thorsen Tools catalog No. 3536 from 1935. (At this time the Thorsen Tool Company was the distributor arm of Thorsen Manufacturing.)

Note the plain hanging hole in the illustration.

The table below the illustration provides the specs for four models, D76, D78, D710, and D712, with sizes 6, 8, 10, and 12 inches respectively.

The finish was chrome plating.

In addition, the text at the far right announces that a new 4 inch model had become available, giving us a 1935 estimate for the first production of this size.


Early Diamalloy 4 Inch Adjustable Wrench

[Diamond Early Diamalloy 4 Inch Adjustable Wrench]
Fig. 21. Diamond Early "Diamalloy" 4 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1935 to Late 1930s.

Fig. 21 shows an early Diamalloy 4 inch adjustable wrench, marked with "Diamalloy Steel" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side. Both sides are also marked with the "4 In." nominal size.

The overall length is 4.3 inches, and the maximum opening is 0.5 inches. The head thickness was measured at 0.31 inches.

The finish is chrome plating with polished faces.

Based on the catalog listing in Fig. 20, the 4 inch model went into production around 1935. The plain hanging hole indicates a relatively earlier production date for this Diamalloy wrench.


Early Diamalloy 6 Inch Adjustable Wrench

[Diamond Early Diamalloy 6 Inch Adjustable Wrench]
Fig. 22. Diamond Early "Diamalloy" 6 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1930s.

Fig. 22 shows an early Diamalloy 6 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side. Both sides are also marked with the "6 In." nominal size.

The overall length is 6.3 inches, and the maximum opening is 0.75 inches. The head thickness was measured at 0.38 inches.

The finish is chrome plating with polished faces.


Early Diamalloy 10 Inch Adjustable Wrench

[Diamond Early Diamalloy 10 Inch Adjustable Wrench]
Fig. 23. Diamond Early "Diamalloy" 10 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1930s.

Fig. 23 shows an early Diamalloy 10 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front. The back side is marked with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side. Both sides are also marked with the "10 In." nominal size.

The overall length is 10.1 inches, and the maximum opening is 1.1 inches. The head thickness was measured at 0.56 inches.

The finish is chrome plating with polished faces.


Broached Hanging Holes

By 1940 Diamond had added a new feature to its adjustable wrenches: a double-hex broached hanging hole. The broached hole was available for both the tool-steel and alloy (Diamalloy) models, but it's an open question as to whether the broached hanging holes were present on all wrenches or as an optional feature.

In the case of the Diamalloy models though, the broaching appears to have been optional, as examples are known of reinforced but not broached holes from around the same time period.

Currently we're unsure of when the broached-hole feature was first offered by Diamond. Our only catalog reference to Diamond production with broached hanging holes is from a 1940 Gamble's Auto Supply catalog, which offered Diamond-made wrenches under the Gamble's and Tiger (alloy) brands. (A later 1942 catalog from Gamble's also shows broached hanging holes.)

The Diamond wrenches illustrated in the Snap-On catalogs from 1927 through 1939 show a plain hanging hole, and a Diamond catalog from the late 1940s shows a reinforced (but not broached) hanging hole.

This leads to an estimate of 1940 to the late 1940s for the broached hole feature. Hopefully we'll be able to find a Diamond catalog from around 1940 to help resolve the questions.

The only other manufacturer known to have offered adjustable wrenches with a broached hole was the J.P. Danielson Company, and its "Bet'R-Grip" brand wrenches were available with this feature from 1933 through 1947.

The next few figures will show examples of Diamond wrenches with broached hanging holes.


Diamalloy 4 Inch Adjustable Wrench with Broached Opening

Broached openings were also available with the Diamalloy-branded alloy steel wrenches, as the next several figures illustrate.

[Diamond Diamalloy 4 Inch Adjustable Wrench]
Fig. 24. Diamond Diamalloy 4 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940 to Late 1940s.

Fig. 24 shows a Diamalloy 4 inch adjustable wrench with a broached hanging hole, marked with "Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side. Both sides are also marked with the nominal size as "8" followed by a double-quote inch mark, and the broached opening is marked with its "5/16" size.

The overall length is 4.3 inches, and the maximum opening is 0.5 inches. The head thickness was measured at 0.34 inches.

The finish is chrome plating with polished faces.


Diamalloy 8 Inch Adjustable Wrenches with Broached Opening

The next two figures show examples of the Diamalloy 8 inch wrench with a broached hole, with minor variations in the markings.

[Diamond Diamalloy 8 Inch Adjustable Wrench]
Fig. 25. Diamond Diamalloy 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940 to Late 1940s.

Fig. 25 shows a Diamalloy 8 inch adjustable wrench with a broached hanging hole, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side. Both sides are also marked with the nominal size as "8" followed by a double-quote inch mark, and the hole is marked with its "9/16" size.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.47 inches.

The finish is chrome plating with polished faces.

[Diamond Diamalloy 8 Inch Adjustable Wrench]
Fig. 26. Diamond Diamalloy 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940 to Late 1940s.

Fig. 26 shows another Diamalloy 8 inch adjustable wrench with a broached hanging hole, but in a variant without the Diamond-Horseshoe logo. The wrench is marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side. Both sides are also marked with the nominal size as "8" followed by a double-quote inch mark, and the hole is marked with its "9/16" size.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.49 inches.

The finish is chrome plating with polished faces.


Diamalloy 12 Inch Adjustable Wrench with Broached Opening

[Diamond Diamalloy 12 Inch Adjustable Wrench]
Fig. 27. Diamond Diamalloy 12 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940 to Late 1940s.

Fig. 27 shows a Diamalloy 12 inch adjustable wrench with a broached hanging hole, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side. Both sides are also marked "12 In." for the nominal size, and the broached hole is marked "3/4" on the back side.

The overall length is 12.2 inches, and the maximum opening is 1.4 inches. The head thickness was measured at 0.73 inches.

The finish is chrome plating with polished faces.


Reinforced Hanging Holes

By the early 1940s Diamond had added a reinforcing ridge around the hanging hole of its Diamalloy adjustable wrenches. This is around the same time that broached hanging holes were first offered, so it appears that the Diamalloy models were available with either option.

By 1948 (or earlier) the broached holes had been discontinued, but Diamond retained the ridge or reinforcing ring around the hanging hole.


Diamalloy 4 Inch Adjustable Wrenches

By the early 1940s Diamond had added a reinforced ridge around the hanging hole of its adjustable wrenches.

[Diamond Diamalloy 4 Inch Adjustable Wrench]
Fig. 28. Diamond "Diamalloy" 4 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 28 shows a Diamond Diamalloy 4 inch adjustable wrench, marked with "Diamalloy Steel" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side. Both sides are also marked with the 4 inch nominal size, using a double-quote mark to denote the inch measure.

The overall length is 4.3 inches, and the maximum opening is 0.5 inches.

The finish is cadmium plating, with some areas of rust or discoloration.

The cadmium finish suggests that this wrench was produced during the wartime years of 1942-1945.

[Diamond Diamalloy 4 Inch Adjustable Wrench]
Fig. 29. Diamond "Diamalloy" 4 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. 1945-1958.

Fig. 29 shows a Diamond Diamalloy 4 inch adjustable wrench, marked with "Diamalloy Steel" and "Made in U.S.A." forged into the front. The back side is marked "Diamond Calk Horseshoe Co." and "Duluth, Minn." with the Diamond-Horseshoe logo. Both sides are also marked with the "4 In." nominal size.

The overall length is 4.3 inches, and the maximum opening is 0.5 inches.

The finish is chrome plating with polished faces.


Diamalloy 6 Inch Adjustable Wrench

[Diamond Diamalloy 6 Inch Adjustable Wrench]
Fig. 30. Diamond "Diamalloy" 6 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. 1945-1958.

Fig. 30 shows a Diamond Diamalloy 6 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front. The back side is marked "Diamond Calk Horseshoe Co." and "Duluth, Minn." with the Diamond-Horseshoe logo. Both sides are also marked with the "6 In." nominal size.

The overall length is 6.3 inches, and the maximum opening is 0.8 inches. The head thickness was measured at 0.39 inches.

The finish is chrome plating.


Diamalloy 8 Inch Adjustable Wrenches

The next two figures show examples of Diamalloy wrenches in the 8 inch size.

[Diamond Diamalloy 8 Inch Adjustable Wrench]
Fig. 31. Diamond "Diamalloy" 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 31 shows an earlier Diamalloy 8 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank. The back side is marked with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the shank, but without the usual Diamond-Horseshoe logo. Both sides are also marked with the 8 inch nominal size, using a double-quote mark to denote the inch measure.

The overall length is 8.0 inches, and the maximum opening is 0.9 inches. The head thickness was measured at 0.49 inches.

The finish is plain steel.

The plain finish suggests production during the 1942-1945 wartime years, when standard chrome-plated finishes were temporarily discontinued.

[Diamond Diamalloy 8 Inch Adjustable Wrench]
Fig. 32. Diamond "Diamalloy" 8 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. 1945-1958.

Fig. 32 shows a somewhat later Diamalloy 8 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the shank. Both sides are also marked with the "8 In." nominal size.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.45 inches.

The finish is chrome plating with polished faces.


Diamalloy 10 Inch Adjustable Wrenches

The next two figures show examples of the 10 inch Diamalloy model.

[Diamond Diamalloy 10 Inch Adjustable Wrench]
Fig. 33. Diamond "Diamalloy" 10 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 33 shows a Diamalloy 10 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side. Both sides are also marked with the "10 In." nominal size.

The overall length is 10.1 inches, and the maximum jaw opening is 1.2 inches. The maximum head thickness was measured at 0.58 inches.

The finish is plain steel.

The plain steel finish with the Diamalloy trademark suggests production during the 1942-1945 wartime years, when standard chrome-plated finishes were temporarily discontinued.


[Diamond Diamalloy 10 Inch Adjustable Wrench]
Fig. 34. Diamond "Diamalloy" 10 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. 1945-1958.

Fig. 34 shows a Diamalloy 10 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side. Both sides are also marked with the "10 In." nominal size.

The overall length is 10.1 inches, and the maximum opening is 1.2 inches. The maximum head thickness was measured at 0.57 inches.

The finish is chrome plating with polished faces.


Diamalloy 12 Inch Adjustable Wrench

[Diamond 12 Inch Adjustable Wrench]
Fig. 35. Diamond "Diamalloy" 12 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. 1942-1945.

Fig. 35 shows a Diamalloy 12 inch adjustable wrench, marked "Forged Steel" and "Made in U.S.A." with the Diamalloy logo in raised letters. The opposite side is marked "Diamond Calk Horseshoe Co." and "Duluth, Minn.", but without the usual Diamond-Horseshoe logo.

The overall length is 12.2 inches, and the maximum opening is 1.4 inches. The maximum head thickness was measured at 0.73 inches.

The finish is plain steel.

The plain steel finish with the Diamalloy trademark suggests production during the 1942-1945 wartime years, when standard chrome-plated finishes were temporarily discontinued.

The Diamalloy 12 inch wrenches use a 1/4-32 by 1.38 inch pin to secure the adjusting knurl, with the threaded end on the inside. (This is a non-standard thread pitch.)


Diamalloy 15 Inch Adjustable Wrenches

The next two figures show examples of Diamalloy wrenches in the 15 inch size.

[Diamond Diamalloy 15 Inch Adjustable Wrench]
Fig. 36. Diamond "Diamalloy" 15 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 36 shows a Diamalloy 15 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." forged into the back side.

The overall length is 15.4 inches, and the maximum opening is 1.7 inches. The maximum head thickness was measured at 0.98 inches.

The finish is plain steel, and the faces show traces of machining or coarse grinding operations.

The plain finish suggests production during the 1942-1945 wartime years.

This wrench has a reinforced hanging hole, although it's not yet known whether earlier wrenches of this size had plain holes.


[Diamond Diamalloy 15 Inch Adjustable Wrench]
Fig. 37. Diamond "Diamalloy" 15 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940s to 1958.

Fig. 37 shows a Diamalloy 15 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

The overall length is 15.4 inches, and the maximum opening is 1.8 inches. The maximum head thickness was measured at 0.93 inches.

The finish is chrome plating.

This wrench has a reinforced hanging hole, although it's not yet known whether earlier wrenches of this size had plain holes.


Double-Ended Wrenches

By 1925 Diamond was offering double-ended adjustable wrenches in four size combinations: 4-6, 6-8, 8-10, and 10-12 inches nominal. The construction of the double-ended models was basically the same as the standard models, so that the combined unit resembled two standard models joined at the shank, with an overall length about the same as the larger of the two sizes.

Double-ended wrenches were produced in both "Tool Steel" and "Diamalloy" models, and the markings on the wrenches were basically the same as for the single-ended versions of the same era. Double-ended wrenches remained in production until the 1960s or later.

The double-ended models were sold at prices typically somewhat lower than the sum of the two standard models of the included sizes, so that a customer intending to buy two single-ended wrenches might consider the double-ended model instead.

We have several examples of Diamond double-ended wrenches and will add them as time pernits.


Early "Tool Steel" 10-12 Inch Double-Ended Adjustable Wrench

[Diamond Tool Steel 10-12 Inch Double-Ended Adjustable Wrench]
Fig. 38. Diamond "Tool Steel" 10-12 Inch Double-Ended Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Mid to Late 1920s.

Fig. 38 shows an early Diamond 10-12 inch double-ended adjustable wrench, marked with "Diamond" and "Tool-Steel Drop-Forged" forged into the shank, with "Diamond Calk Horseshoe Co." and "Duluth, Minn. U.S.A." forged into the back side. The wrench is also marked with the sizes and the Diamond-Horseshoe logo forged into both sizes, and a small forged-in code "A508" appears on the back side, just below the adjusting knurl on the right (see middle inset).

The overall length is 12.2 inches, and the maximum openings are 1.2 and 1.4 inches. The head thicknesses were measured at 0.71 and 0.84 inches.

The finish is plain steel, with extensive pitting due to rust.

The "Duluth, Minn. U.S.A." marking suggests an early production date for this example.


Diamalloy 6-8 Inch Double-Ended Adjustable Wrench

[Diamond Diamalloy 6-8 Inch Double-Ended Adjustable Wrench]
Fig. 39. Diamond "Diamalloy" 6-8 Inch Double-Ended Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1942-1945.

Fig. 39 shows a later Diamalloy 6-8 inch double-ended adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front, with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the back side.

Both sides are also marked with the 6 and 8 inch nominal sizes, with a double-quote mark to denote the inch measure.

The overall length is 8.0 inches, and the maximum openings are 0.8 and 1.0 inches. The head thicknesses were measured at 0.40 and 0.51 inches.

The finish is cadmium plating.

The cadmium finish suggests production during the 1942-1945 wartime years.


A New Company Name

In 1958 the Diamond Calk Horseshoe Company changed its name to "Diamond Tool and Horseshoe", and tools marked with this name can be assumed to be from 1958 or later.


"Tool Steel" 12 Inch Adjustable Wrench

[Diamond 12 Inch Adjustable Wrench]
Fig. 40. Diamond 12 Inch Adjustable Wrench, with Insets for Side View and Marking Detail, ca. 1959-1982.

Fig. 40 shows a later Diamond 12 inch adjustable wrench, marked with the Diamond logo forged into the shank, followed by "Tool-Steel Drop-Forged" and "Made in U.S.A." in forged raised letters.

The back side marked "Diamond Tool and Horseshoe Co." and "Duluth, Minn." in raised letters with the Diamond-Horseshoe logo.

The overall length is 12.2 inches, and the maximum opening is 1.3 inches. The head thickness was measured at 0.73 inches.

The finish is nickel plating.

Note that the company name on this tool is now "Diamond Tool and Horseshoe" instead of "Diamond Calk Horseshoe", and a glance at the horseshoe logo shows that the diamond no longer has a calk.


Diamalloy 8 Inch Adjustable Wrench

[Diamond Diamalloy 8 Inch Adjustable Wrench]
Fig. 41. Diamond Diamalloy 8 Inch Adjustable Wrench, with Inset for Back Side Detail, ca. 1959-1982.

Fig. 41 shows a later Diamalloy 8 inch adjustable wrench, marked with "Diamalloy Alloy Steel" and "Forged in U.S.A." forged into the shank.

The opposite side is marked "Diamond Tool and Horseshoe Co." and "Duluth, Minn." with the Diamond-Horseshoe logo.

The overall length is 8.1 inches, and the maximum opening is 0.9 inches. The head thickness was measured at 0.45 inches.

The finish is chrome plating with polished faces.


Pliers and Other Tools

Diamond appears to have begun producing pliers sometime in the late 1920s to early 1930s, although due to a lack of catalog coverage we're uncertain of the exact date. However, published references in Hardware Age (and other publications) indicate that Diamond slip-joint pliers were definitely in production by 1931.


Slip-Joint Pliers

By the early 1930s Diamond was offering several models of slip-joint pliers.


"Motor Spec" (Diamond) K18 8 Inch Combination Pliers

[Diamond K18 Motor Spec 8 Inch Combination Pliers]
Fig. 42. "Motor Spec" (Diamond) K18 8 Inch Combination Pliers, with Inset for Side View.

Fig. 42 shows a pair of "Motor Spec" K18 8 inch combination pliers, stamped "Motor Spec" and "Duluth USA" near the pivot, with "Made in U.S.A." forged into the handles.

The overall length is 7.9 inches, and the finish is plain steel, or possibly cadmium plating.


"Motor Spec" (Diamond) K110 10 Inch Combination Pliers

[Motor Spec (Diamond) K110 10 Inch Combination Pliers]
Fig. 43. "Motor Spec" (Diamond) K110 10 Inch Combination Pliers, with Inset for Side View.

Fig. 43 shows a pair of "Motor Spec" K110 10 inch combination pliers, stamped "Motor Spec" and "Duluth USA" near the pivot, with "Made in U.S.A." forged into the handles.

The overall length is 9.8 inches, and the finish is plain steel, with minor pitting due to rust.


Diamond K36 6 Inch Combination Pliers

[Diamond K36 6 Inch Combination Pliers]
Fig. 44. Diamond K36 6 Inch Combination Pliers, with Inset for Side View.

Fig. 44 shows a pair of Diamond K36 6 inch combination pliers, stamped "Duluth, USA" with the Diamond and Diamond-Horseshoe logos, and with "U.S.A." forged into the handles.

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


Diamond Diamalloy H16 6 Inch Combination Pliers

In some of Diamond's later production the company name was dropped in favor of the Diamalloy logo, as the next example illustrates.

[Diamond Diamalloy H16 6 Inch Combination Pliers]
Fig. 45. Diamond Diamalloy H16 6 Inch Combination Pliers, with Inset for Handle Pattern.

Fig. 45 shows a pair of Diamalloy H16 6 inch combination pliers, stamped "Duluth, USA" with the Diamalloy and Diamond-Horseshoe logos, and with "Forged in U.S.A." forged into the handles.

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


Diamond M26 6 Inch Bent Thin-Nose Combination Pliers

[Diamond M26 6 Inch Bent Thin-Nose Combination Pliers]
Fig. 46. Diamond M26 6 Inch Bent Thin-Nose Combination Pliers, with Inset for Side View.

Fig. 46 shows a pair of Diamond M26 6 inch bent thin-nose combination pliers, stamped "Duluth USA" with the Diamond logo near the pivot, and with "Forged in U.S.A." forged into the handles.

The overall length is 6.6 inches, and the finish is chrome plating.


Diamond N18 8 Inch Thin-Nose Combination Pliers

[Diamond N18 8 Inch Thin-Nose Combination Pliers]
Fig. 47. Diamond N18 8 Inch Thin-Nose Combination Pliers, with Inset for Side View.

Fig. 47 shows a pair of Diamond N18 8 inch thin-nose combination pliers, stamped "Duluth USA" with the Diamond logo near the pivot, and with "Made in U.S.A." forged into the handles.

The overall length is 7.9 inches, and the finish is plain steel or black oxide.


Diamalloy KC-18 Hose Clamp Pliers

[Diamond Diamalloy KC-18 Hose Clamp Pliers]
Fig. 48. Diamond Diamalloy KC-18 Hose Clamp Pliers, with Insets for Side View and Marking Detail.

Fig. 48 shows a pair of Diamond Diamalloy KC-18 hose clamp pliers, stamped "Duluth USA" with the Diamalloy logo near the pivot, and with "Forged in U.S.A." forged into the handles.

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


Fixed-Pivot Pliers

By 1935 Diamond was offering fixed-pivot fencing pliers, and cutting pliers such as diagonal cutters and linemen's pliers came somewhat later. Currently our earliest reference to diagonal cutters is from 1941.

Fixed-pivot pliers (including battery pliers) were offered only in "Diamalloy" alloy steel.


Diamond HB28 8 Inch Battery Pliers

[Diamond HB28 8 Inch Battery Pliers]
Fig. 49. Diamond HB28 8 Inch Battery Pliers, with Insets for Side View and Marking Detail.

Fig. 49 shows a pair of Diamond HB28 8 inch battery pliers, stamped "Duluth USA" with the Diamond logo near the pivot.

The overall length is 7.9 inches, and the finish is chrome plating.

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


Diamalloy SL56 6 Inch Lineman's Pliers

[Diamond Diamalloy SL56 6 Inch Lineman's Pliers]
Fig. 50. Diamond Diamalloy SL56 6 Inch Lineman's Pliers, with Inset for Side View.

Fig. 50 shows a pair of Diamalloy SL56 6 inch lineman's pliers, marked "Diamond Duluth" and "Made in U.S.A." near the pivot.

The overall length is 6.4 inches, and the finish is plain steel.


Diamalloy SN56 6 Inch Needlenose Pliers with Side Cutters

[Diamond Diamalloy SN56 6 Inch Needlenose Pliers]
Fig. 51. Diamond Diamalloy SN56 6 Inch Needlenose Pliers, with Inset for Side View.

Fig. 51 shows a pair of Diamalloy SN56 6 inch needlenose pliers with side cutters, marked "Diamond Duluth" and "Made in U.S.A." near the pivot.

The overall length is 6.6 inches, and the finish is plain steel.


Diamalloy S56 6 Inch Diagonal Cutters

[Diamond Diamalloy S56 6 Inch Diagonal Cutters]
Fig. 52. Diamond Diamalloy S56 6 Inch Diagonal Cutters, with Inset for Side View.

Fig. 52 shows a pair of Diamalloy S56 6 inch diagonal cutters, marked "Diamond Duluth" and "Made in U.S.A." near the pivot.

The overall length is 6.1 inches, and the finish is plain steel.


Diamalloy G57 7 Inch End Nippers

[Diamond Diamalloy G57 7 Inch End Nippers]
Fig. 53. Diamond Diamalloy G57 7 Inch End Nippers, with Inset for Side View.

Fig. 53 shows a pair of Diamalloy G57 7 inch end nippers, stamped with the Diamalloy logo and "Duluth" near the pivot.

The overall length is 7.3 inches, and the finish is plain steel.


"Handiman" and "Handyboy" Combination Tools

In the 1940s Diamond introduced a distinctive "Handiman" combination tool with the functionality of pliers, wire cutters, adjustable wrench, and screwdriver in one tool. Legend has it that these were developed for use by ski troops in Finland during World War II, although we don't have a definitive reference for this. In any event, the Handiman tool remained popular after the war and was later rebranded as "Handiboy".


Diamalloy DH16 "Handiman" 6 Inch Combination Tool

[Diamond Diamalloy DH16 Handiman 6 Inch Combination Tool]
Fig. 54. Diamond Diamalloy DH16 "Handiman" 6 Inch Combination Tool, with Insets for Marking Detail.

Fig. 54 shows an older example of the Diamond's popular "Handiman" combination tool, a pair of Diamond DH16 6 inch slip-joint combination pliers with an adjustable wrench as one handle.

The pliers are marked "Handiman Duluth" with the Diamalloy trademark logo, with "Forged in U.S.A." forged into the back side of one handle.

The overall length is 6.4 inches. The finish is chrome plating, with losses due to wear revealing the copper underlayer.


Diamalloy DH18 "Handyboy" 8 Inch Combination Tool

[Diamond Diamalloy DH18 Handyboy 8 Inch Combination Tool]
Fig. 55. Diamond Diamalloy DH18 "Handyboy" 8 Inch Combination Tool.

Fig. 55 shows an example of the popular "Handyboy" combination tool, a pair of Diamond DH18 8 inch slip-joint combination pliers with an adjustable wrench as one handle. The pliers are marked "Handyboy Duluth" with the Diamalloy trademark logo, and "U.S.A." is forged into one handle.

The overall length is 7.8 inches, and the finish is polished chrome.

This particular tool is relatively recent, having been purchased new in the 1980s.


"Groove-Joint" Tongue-and-Groove Pliers

In the early 1950s W.V. Daugherty of Utica Drop Forge & Tool developed a method of directly forging the curved ribs for tongue-and-groove pliers, which was described by the 1952 patent 2,622,464. Diamond licensed the patent and by late in 1951 had introduced a line of tongue-and-groove pliers under the "Groove-Joint" trademark.

In the early 1970s Diamond made a further improvement to the tongue-and-groove design with patent 3,739,664, filed in 1971 by J.E. Swanstrom Jr. and issued in 1973. This patent describes a method of forging the curved ribs of the pliers with an undercut edge.


Diamalloy HL18 8 Inch "Groove-Joint" Tongue-and-Groove Pliers

[Diamond Diamalloy HL18 8 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 56. Diamond Diamalloy HL18 8 Inch "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 56 shows a pair of Diamalloy HL18 8 inch tongue-and-groove pliers, stamped with the Diamalloy and Diamond-Horseshoe logos, followed by "Groove-Joint" and "Duluth, U.S.A." at the bottom.

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


Diamalloy HL19½ 9.5 Inch "Groove-Joint" Tongue-and-Groove Pliers

[Diamond Diamalloy HL19½ 9.5 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 57. Diamond Diamalloy HL19½ 9.5 Inch "Groove-Joint" Tongue-and-Groove Pliers, ca. Early to Mid 1950s.

Fig. 57 shows an early pair of Diamalloy HL19½ 9.5 inch tongue-and-groove pliers, stamped with the Diamalloy logo followed by "Groove-Joint" and "Duluth, U.S.A.", and with "Licensed" at the bottom.

The overall length is 9.7 inches, and the finish is chrome plating.

The "Licensed" marking is a reference to the patent #2,622,464 licensed from Utica Drop Forge & Tool.

The "Licensed" marking suggests production in the early to mid 1950s.


Diamalloy HL112 12 Inch "Groove-Joint" Tongue-and-Groove Pliers

[Diamond Diamalloy HL112 12 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 58. Diamond Diamalloy HL112 12 Inch "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 58 shows a pair of Diamalloy HL112 12 inch tongue-and-groove pliers, marked "Groove-Joint" and "Duluth, U.S.A." with the Diamalloy logo. (The markings are a bit difficult to read, but are located above and to the right of the pivot.)

The overall length ranges from 11.9 inches closed to 12.4 inches fully extended, and the finish is chrome plating.


Diamalloy HL18P 8 Inch "Groove-Joint" Tongue-and-Groove Pliers

In the early 1970s J.E. Swanstrom Jr. of Diamond Tool developed and patented a significant improvement for tongue-and-groove pliers. The next figure shows an example of this patent on Diamalloy pliers, and a later figure shows the patent on Blue Point HL112P Pliers.

[Diamalloy HL18P 8 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 59. Diamalloy HL18P 8 Inch "Groove-Joint" Tongue-and-Groove Pliers, with Insets for Construction and Marking Detail, ca. 1973+.

Fig. 59 shows a pair of Diamalloy HL18P 8 inch "Groove-Joint" tongue-and-groove pliers, stamped "U.S.A." with the Diamond-Horseshoe logo, and with a "Pat. 3739664" patent notice.

The overall length is 8.1 inches, and the finish is chrome plating with plastic hand grips.

The upper left inset in the photograph shows the distinctly undercut edges of the ribs, which helps to hold the jaws of the pliers together under stress.

The patent notice refers to patent #3,739,664, issued to J.E. Swanstrom Jr. in 1973. The patent describes a method of forging that allows the curved ribs of the pliers to be directly forged with an undercut edge.

This patent was a significant improvement to the state of the art for tongue-and-groove pliers, as it combined the desirable undercut ribs described in Manning patent #2,640,381 with the forged ribs developed by Daugherty in patent #2,622,464.


Contract Production

In addition to producing tools for its own brands, Diamond Calk also provided contract manufacturing services to other companies, and the resulting tools were marked with the customer's brand. This section will show some examples of Diamond Calk production for other companies.


Kelley-How-Thomson (K.H.T.) Company

In the 1920s Diamond produced adjustable wrenches marked with the "Hickory" brand for the Kelley-How-Thomson (K.H.T.) Company of Duluth, Minnesota. K.H.T was a wholesale hardware company formed around 1896 as the Kelley Hardware Company. Further information on this company can be found in a 1910 publication History of Duluth and St. Louis County in the section on Kelley-How-Thomson.


K.H.T. "Hickory" 8 Inch Adjustable Wrench

[K.H.T. Hickory 8 Inch Adjustable Wrench]
Fig. 60. K.H.T. "Hickory" 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1920s.

Fig. 60 shows a K.H.T. "Hickory" 8 inch adjustable wrench, marked with "Made By Diamond Calk Horseshoe Co." and "Duluth Minn. U.S.A." forged into the shank, with "Hickory" and "K.H.T. Co. Duluth Minn." forged into the back side.

The shank also has a forged-in Diamond-Horseshoe logo near the hanging hole.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.53 inches.

The finish is plain steel.

This wrench has some details in common with the early Diamond production, including the use of the "Duluth Minn U.S.A." marking, and a rough edge left by the trimming operation.


Montgomery Ward

Montgomery Ward sold tools under a number of brand names, including Riverside, Powr-Kraft, and Ward's Master Quality.


Ward's "Master Quality" 12 Inch Adjustable Wrench

[Ward's Master Quality 12 Inch Adjustable Wrench]
Fig. 61. Ward's Master Quality 12 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1930s.

Fig. 61 shows a Ward's "Master Quality" 12 inch adjustable wrench, marked with "Wards Master Quality" stamped on both sides of the shank. The shank is also marked with the 12 inch size and "Drop Forged" forged into the front, with the size and "Made in U.S.A." forged into the back side.

The overall length is 12.2 inches, and the maximum opening is 1.3 inches. The head thickness was measured at 0.70 inches.

The finish is chrome plating with polished faces, with minor losses due to wear.


Ward's "Master Quality" 8 Inch Adjustable Wrench

[Ward's Master Quality 8 Inch Adjustable Wrench]
Fig. 62. Ward's Master Quality 8 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940s.

Fig. 62 shows a Ward's "Master Quality" 8 inch adjustable wrench with a broached hanging hole, marked with "Wards Master Quality" and "Drop Forged" forged into the shank, with "Molybdenum Alloy" and "Made in U.S.A." forged into the back side, along with the "9/16" size near the broached end.

The overall length is 8.1 inches, and the maximum opening is 1.0 inches. The head thickness was measured at 0.49 inches.

The finish is chrome plating with polished faces, with some loss due to wear.

This wrench is easily identified as Diamond Calk production by the construction and markings. We first note that this example is nearly identical in dimensions and features to the Diamalloy 8 Inch Wrench with Broached Opening shown in an earlier figure. The broached hanging hole in particular is an unusual feature for adjustable wrenches, with only two companies known to have made wrenches in this style: Diamond Calk Horseshoe and J.P. Danielson.

An example of the corresponding Danielson model can be seen as the Danielson "Vanadium" 8 Inch Adjustable Wrench in our article on J.P. Danielson. Although the Danielson wrench is similar to the example here, one major difference is the square jaw opening used by Danielson, instead of the hexagonal jaw found on Diamond Calk production.


Ward's "Master Quality" 6 Inch Adjustable Wrench

[Ward's Master Quality 6 Inch Adjustable Wrench]
Fig. 63. Ward's Master Quality 6 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. 1940s.

Fig. 63 shows a later Ward's "Master Quality" 6 inch adjustable wrench, marked with "Wards Master Quality" and "84-4701" forged into the shank, with "Molybdenum Alloy" plus "Drop Forged" and "Made in U.S.A." forged into the back side.

The overall length is 6.2 inches, and the maximum opening is 0.8 inches. The head thickness was measured at 0.39 inches.

The finish is chrome plating with polished faces, with some loss due to wear.


Gamble Stores

Gamble-Skogmo, Incorporated operated a chain of Gamble Stores selling home furnishings and auto accessories, including a selection of automotive service tools. Their tool brands included "Artisan" and "Tiger Tools".


Tiger Tools Adjustable Wrenches

[1940 Catalog Listing for Tiger Alloy Adjustable Wrenches]
Fig. 64. 1940 Catalog Listing for Tiger Alloy Adjustable Wrenches.

The scan in Fig. 64 shows a listing for Gamble's and Tiger Alloy adjustable wrenches, as published on page 49 of the 1940 Gamble's Auto Supply catalog.

The wrenches in the illustration can be identified as Diamond production by the forged-in markings. The "Gamble's" wrenches would be the Diamond tool steel models, and the "Tiger Alloy" were the Diamalloy models.

Note that the wrenches are illustrated with broached hanging holes, and the text refers to the "12-point box-end wrench" in the handles. The 1940 Gamble's catalog (and a later one from 1942) are currently the only catalogs known to offer Diamond wrenches with broached hanging holes.

A similar listing appeared in the 1942 Gamble's catalog.

Currently we do not have an example of a Tiger Tools adjustable wrench, but are displaying this catalog listing as a placeholder.


Western Auto Supply

Western Auto Supply was a high-volume retailer of auto accessories, including a wide variety of tools. The company actually operated as separate Eastern and Western branches, with different management and a somewhat different product mix.

Both branches of Western Auto Supply used the "Western Giant" brand for automobile tires from before 1920 into the 1930s. The brand was later used for automobile accessories, and during the 1930s the Western branch used "Western Giant" for tools as well.

Tools found with the Western Giant brand include socket sets, open-end wrenches, combination wrenches, and adjustable wrenches.

More information on the company can be found in our article on Western Auto Supply.


Western Giant 6 Inch Adjustable Wrench

[Western Giant 6 Inch Adjustable Wrench]
Fig. 65. Western Giant 6 Inch Adjustable Wrench, with Insets for Side View and Back Side Detail, ca. Early 1940s.

Fig. 65 shows a Western Giant 6 inch adjustable wrench, stamped with "Western Giant" and "Heavy Duty Tools" on both sides of the shank.

The shank is also marked with "Drop Forged" forged into the front, with "Made in U.S.A." forged into the back side.

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

This tool can be recognized as Diamond production by the broached hanging hole and forged-in markings.

Diamond introduced the broached hole around 1940, leading to an early 1940s production estimate.

A similar example from Diamond can be seen as the Diamond 6 Inch Adjustable Wrench.


Snap-on/Blue Point


Blue-Point HL112P 12 Inch Tongue-and-Groove Pliers

[Blue-Point HL112P 12 Inch Tongue-and-Groove Pliers]
Fig. 66. Blue-Point HL112P 12 Inch Tongue-and-Groove Pliers, with Inset for Construction Detail, ca. 1973+.

Fig. 66 shows a pair of Blue-Point HL112P 12 inch tongue-and-groove pliers, marked "Made in U.S.A." with a "Pat. 3739664" patent notice.

The overall length ranges from 11.9 inches closed to 12.4 inches fully extended, and the finish is chrome plating.

The upper inset in the photograph shows the distinctly undercut edges of the ribs, which helps to hold the jaws of the pliers together under stress.

The patent notice refers to patent #3,739,664, issued to J.E. Swanstrom Jr. in 1973. The patent describes a method of forging that allows the curved ribs of the pliers to be directly forged with an undercut edge.


Post-Triangle Production

In 1981 Diamond Tool was conglomerated into the Triangle Corporation, which at the time also owned the Bonney, Herbrand, and Utica tool brands. Later corporate changes brought Triangle into the Cooper Tools conglomerate, which also owned the Crescent brand.

In later years the Diamond adjustable wrenches were produced in a different design closely resembling the Crescent brand wrenches. This design can be easily recognized by the depressed panel of the handle, which extends all the way to the adjusting screw.


Diamond 10 Inch Wide Adjustable Wrench

[Diamond 10 Inch Wide Opening Adjustable Wrench]
Fig. 67. Diamond 10 Inch Wide Opening Adjustable Wrench, ca. 1983+.

Fig. 67 shows a later Diamond 10 inch wide opening adjustable wrench, marked with the Diamond logo plus "Wide Opening" and "No Hammering" forged into the shank, with "U.S.A." on the back side (not shown).

The overall length is 10.0 inches. The jaws of this model open up to about 1.3 inches, compared to about 1.1 inches for a standard 10 inch wrench. The maximum head thickness was measured at 0.57 inches.

The finish is chrome plating with polished faces.

This example shows the different design used by later Diamond-brand wrenches, with the depressed panel extended all the way to the adjusting screw. (For a comparison with the Crescent design, see the Crescent Late Adjustable Wrench.)


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