Armstrong Bros. Tool Company

Logo from 1914 Trademark.

Table of Contents

Introduction

Company History

The Armstrong Bros. Tool Company began in 1890 as a maker of bicycle parts and service tools, founded in Chicago, Illinois by five brothers. (Some sources say four brothers, but the ABHB names them as James, George, John, Paul, and Hugh.) Their first manufacturing operations were conducted literally from a backyard wooden shed, and the brothers also operated a retail store for their bicycle parts.

In 1895 Armstrong introduced what would become their first major product, a tool holder for lathe cutting bits. Developed from their own manufacturing operations, the Armstrong tool holder was a forged handle that accepted small interchangeable cutting bits, thereby replacing the individually forged cutting tools previously required. This dramatically reduced the time and expense involved in making lathe cutting tools, and it's fair to say that these tool holders revolutionized the industry.

With the success of the tool holder, in 1900 Armstrong built their first real factory at 617 Austin Avenue in Chicago.

Fig. 1A. 1901 Notice for Armstrong Wrenches.

Fig. 1A shows a notice of the move to Austin Avenue, as published on page 27 of the January 31, 1901 issue of Iron Age.

The text of the article provides quite a bit of detail regarding Armstrong's operations at the new factory.

In 1905 Armstrong moved again, this time to a 100,000 square foot brick factory at 317 North Francisco Avenue, a site they would occupy for many years.

The Universal Ratchet Drill

One of Armstrong's earliest non-toolholder products was a ratchet drill with a universal handle. The ratchet was based on a brilliant 1892 patent in which five pawls are arranged to progressively engage a 12-tooth ratchet gear, providing an effective 60-tooth action.

Wrench Production

Up until 1909 Armstrong concentrated primarily on tool holders and related products, but in 1909 they started producing a line of drop-forged wrenches. This line of tools continued to expand over the years.

Fig. 1. 1915 Advertisement for Armstrong Wrenches.

The scan in Fig. 1 shows an advertisement for Armstrong wrenches, as published on page 52 [External Link] of the April, 1915 issue of Mill Supplies.

The illustration shows a number of the company's drop-forged wrenches, incuding tool-post, textile, and S-shaped designs, as well as a range of standard double-open wrenches. Note that most of the wrenches in the illustration show the A-Triangle logo.

By 1918 Armstrong had become one of the "Big Nine" of the forging industry: nine companies who together accounted for nearly all of the drop-forged wrench production. These companies jointly signed a Conservation Agreement to reduce manpower and materials, as requested by the War Industries Board.

"Aero" Tappet Wrenches and Alloy Steel

In 1919 Armstrong began offering three sizes of "Aero" tappet wrenches made of chrome-nickel steel, an early example of alloy steel usage for tools. The "Aero" wrenches were significant as the earliest known drop-forged wrenches made of alloy steel. (The 1919 date was noted in the 1927 catalog and on page 21 of the ABHB brochure.)

Our earliest published reference to the "Aero" wrenches is from 1920.

Fig. 2. 1920 Notice for Armstrong B-20 Catalog. [External Link]

Fig. 2 shows a notice announcing Armstrong catalog B-20, as published on page 748 of the November, 1920 issue of Railway Mechanical Engineer. The text notes the inclusion of "Aero" tappet wrenches among the new products.

Fig. 3. 1920 Catalog Listing for "Aero" Tappet Wrenches.

The scan in Fig. 3 shows the listing for the "Aero Six" tappet wrench set as it appeared on page 125 of catalog B-20.

The set offered six wrenches with two each of the three models A-6 (7/16x1/2), A-7 (9/16x5/8), and A-8 (3/4x7/8). The "Aero" wrenches were designed with the same 15 degree offset heads as a standard Engineer's wrench, but with a slightly greater length for the two smaller models.

The "Aero" wrenches were listed on the first page of the "Automotive Wrench" section of the catalog, but were the only alloy-steel tools in the section. The "Aero" models were relatively expensive at first, with prices more than three times as high as Armstrong's carbon-steel tappet wrenches.

By 1923 Armstrong had realized that the market for automotive service tools was much bigger than that for airplane service, and "Aero" tappet wrenches were being promoted for automotive applications. One additional size had been added, a model B-8 at 11/16x13/16, and catalog B-23 noted that the No. 88 set of 8 "Aero" wrenches would service tappets on 70 makes of automobiles.

The prices for the "Aero" wrenches had decreased significantly by this time, suggesting that they were being made in quantity.

It's interesting to speculate that if Armstrong had followed up with a full line of alloy-steel wrenches in the early 1920s, they might have been able to displace Bonney as the market leader in these new tools. But as history played out, Armstrong waited until around 1927 to expand its line of alloy tools.

In the mean time, by late 1922 Bonney had begun offering its "CV" Line of chrome-vanadium alloy steel wrenches to universal acclaim.

The Armstrong-Vanadium Line

By 1927 Armstrong was offering the Armstrong-Vanadium line of chrome-vanadium alloy steel wrenches, initially as double-open Engineer's wrenches and tappet wrenches.

The "Aero" tappet wrenches were still available in 1927, but the Armstrong-Vanadium line offered a 40x model series of tappet wrenches based on Bonney's design. The 40x series featured two openings of the same size, with one head offset by 22.5 degrees. An example can be seen as the Armstrong-Vanadium 403 9/16x9/16 Tappet Wrench.

Collaboration with Blackhawk Manufacturing

In 1928, shortly after the introduction of the Armstrong-Vanadium line, Armstrong began a highly successful collaboration with Blackhawk Manufacturing for the Blackhawk-Armstrong line of wrenches. The arrangement with Blackhawk was somewhat unusual in that Armstrong provided contract manufacturing, but also received name recognition from the joint company marking.

In the late 1920s Blackhawk was very well known in the automotive service market, especially for interchangeable socket tools. In 1919 Blackhawk had been the first company to offer heavy-wall interchangeable sockets in the standard 1/2-drive, and the success of these socket tools made Blackhawk an industry leader in the 1920s. In contrast, Armstrong was well known among machinists and industrial customers, but with the exception of its "Aero" tappet wrenches, Armstrong's tools were not well suited for automotive service.

As an automotive tools specialist, Blackhawk helped push Armstrong into developing specialty wrenches for the line, such as angle-head obstruction wrenches, brake wrenches, and eventually offset box-end wrenches. Some of these tools were also added to the Armstrong-Vanadium line as well.

From the ABHB we learned of another previously unknown facet of the Blackhawk-Armstrong collaboration. Page 21 of the ABHB notes that in return for providing forged wrenches to Blackhawk, Armstrong received sockets and drive tools from Blackhawk! Since the Armstrong catalog B-27 from 1927 did not offer sockets and drive tools, we were surprised to learn that Armstrong had entered this market in the late 1920s.

It's not yet clear how these socket tools were marked (Armstrong-Blackhawk?) or marketed, since we don't have any catalog coverage. Armstrong had many industrial customers who could have been interested in socket tools, but these customers could also have purchased Blackhawk directly. (Like Armstrong, Blackhawk was also carried by many industrial distributors.)

Due to an awkward gap in available catalogs, Armstrong's socket line remains undocumented until 1935. We hope that additional Armstrong catalogs will be discovered for the late 1920s to early 1930s period.

The Early 1930s

The early 1930s were a time of great economic distress in America, and Armstrong was forced to make changes in order to survive. According to the ABHB, in 1931 Armstrong relaxed a company policy against selling to mass-market retailers and took a large order from Montgomery Ward, a mail-order retailer comparable to Sears Roebuck but on a smaller scale. Armstrong supplied Ward with long-handled axes and five-piece wrench sets.

As an aside, we haven't run across any Armstrong production for Montgomery Ward, but would be interested in learning more about the wrench sets, specifically about how they were marked. Other tool companies such as Herbrand provided contract manufacturing during the 1930s for the Ward's "Riverside" brand.

Socket Production

Armstrong made another important change after their management realized that 32 of their automatic screw machines were sitting idle. Screw machines are large and expensive lathes capable of automated production of almost anything that can be turned from a bar of metal. Since Armstrong was still receiving sockets from Blackhawk at the time, the company decided to pull this production in-house and make their own sockets. This first step turned into a decision to make a full line of socket tools.

The ABHB gives a mid 1930s timeline for socket production, but we think it must have started by 1933 or earlier, in order for the company to be able to offer a full line of socket tools in the 1935 catalog.

With the release of catalog B-35 in 1935 Armstrong's line of sockets and drive tools was finally documented. By this time the company had a full line of tools available, with drive sizes from 1/4 to 3/4 in square drive, plus 1 inch hex drive. (The 1 inch hex drive size appears to have originated with Walden-Worcester, and was also offered by J.H. Williams in the early 1930s.)

Chromium Vanadium and Western Auto Supply

Earlier in this section we mentioned Armstrong's production for Montgomery Ward, the only such retailer noted in the ABHB. However, we can offer strong evidence that Armstrong made tools for an even more important mass-market retailer, specifically Western Auto Supply. Western Auto specialized in auto accessories, and goods were sold both from a network of stores and by mail order. Tools were a major part of their business, and during the 1930s tool manufacturers probably fought tooth-and-nail to gain business from Western Auto.

Beginning in 1931 Western Auto Supply started using "Chromium Vanadium" (the full element names) as a brand for its alloy steel tools, and it asked its manufacturing partners to mark their production accordingly. Since most of their suppliers were already using chrome-vanadium steel, the minor change in marking was not a problem. And for latter-day tool sleuths (that's us), the use of "Chromium Vanadium" turned out to be very valuable in tracking production for Western Auto.

It turns out that a number of Armstrong tools have been observed with a "Chromium Vanadium" marking instead of the usual "Chrome Vanadium". We've gone through all of the tools in this article and have carefully indexed the ones with this particular marking, using "Chromium Vanadium" as the heading and "on Armstrong xxx" as the sub-heading. Checking the site index then revealed a substantial collection, as can be seen in the list below.

• Tappet Wrenches (Armstrong 422, Armstrong 426)
• Obstruction Wrenches (Armstrong 2029)
• Box-end Wrenches (Armstrong 8727, Armstrong 5037)
• 1/2-drive Sockets (Armstrong S-1224, Armstrong ST-1224)
• 3/4-drive Sockets, (Armstrong H-1230, Armstrong H-1231)
• 1 Inch Hex Drive (!) Sockets (Armstrong X-1252, Armstrong X-1258)

We can't recall seeing Armstrong listed as a vendor in the Western Auto catalogs, but it's possible that a more careful reading will turn up an example. Items such as tappet wrenches, obstruction wrenches, box wrenches, and 1/2-drive sockets were very commonly listed in the catalogs, sometimes without indicating the manufacturer.

The heavy-duty tools in the list (the 5037 wrench, 3/4-drive sockets, and 1 inch drive sockets) were not generally listed in Western Auto catalogs, and for these we think that the Western Auto Special Order facility would apply. This is not well documented, but apparently allowed the manager of a store to order from the catalogs of approved vendors.

Western Auto Supply had a significant influence on the tool industry. The company was a very aggressive retailer, and its major suppliers included two very aggressive cost-cutters in Duro/Indestro and Vlchek. As a team, Western Auto and its suppliers were able to push tools into cost-sensitive retail markets at a much faster pace than the slow diffusion from professional markets. Readers seeking a quick introduction can read about the Great Box Wrench Price War in our article on Western Auto.

We hope to find further documentation of Armstrong's association with Western Auto Supply.

From Armstrong-Vanadium to Chrome-Vanadium

Although not mentioned in the ABHB, another important change in the early 1930s was the transition from forged-in Armstrong-Vanadium markings to simpler stamped markings with "Chrome-Vanadium" plus the company name and "Strong-Arm" logo.

The crisp forged-in markings of the earlier era had allowed the company to flaunt the skills of its die-makers, but at a high cost for the creation and maintenance of the forging dies. In addition, the forged-in markings would have been cumbersome for Armstrong's contract production business with Blackhawk, as extra dies had to be created for the "Blackhawk-Armstrong" side of each wrench, and then swapped into the drop-hammer during production.

Although we don't have an exact timeline for the change away from forged-in markings, it probably occurred in the 1932-1933 timeframe, and may have been phased in as the existing forging dies wore out and needed replacement. For a transitional period some tools were given stamped "Armstrong-Vanadium" markings.

With the lower cost structure provided by this change, Armstrong was able to sell to the cost-sensitive but high volume retailer Western Auto Supply mentioned previously, as evidenced by tools such as the Armstrong 422 Tappet Wrench and Armstrong 8727 Box Wrench.

Lower costs also allowed Armstrong to supply box wrenches and combination wrenches to the Blackhawk "HeXo" Line beginning around 1934.

Heavy-Duty Wrenches

By 1937 Armstrong was offering box wrenches with stub handles and tubular extensions.

Fig. 4. 1937 Notice for Armstrong Heavy-Duty Box Wrenches. [External Link]

Fig. 4 shows a notice illustrating several styles of Armstrong heavy-duty box wrenches, as published on page 216 of the June, 1937 issue of Modern Machine Shop.

The illustration shows single-ended box wrenches in straight, angled, and offset styles, with stub handles intended to fit a tubular extension.

The Post-War Era

In 1946 Armstrong began using the "Armaloy" trademark to indicate the use of alloy steel.

In 1948 the company moved from the Francisco Avenue site to 5200 West Armstrong Avenue in Chicago, where they remained for many years.

Fig. 5. 1956 Catalog Illustration of Armstrong Factory.

The scan in Fig. 5 shows an illustration of Armstrong's factory at 5200 West Armstrong, as published on the first page of catalog 57 from 1956.

A second manufacturing facility in Fayetteville, Arkansas was added in 1974.

Acquisition by Danaher

In 1994 Armstrong was acquired by the Danaher Group, a conglomerate with other tool company holdings including Allen, K-D, Matco, and Easco, the latter of which held the Sears Craftsman production contract at that time. After the acquisition Armstrong continued to operate as the Industrial Hand Tools division of Danaher.

Danaher later acquired the innovative "GearWrench" line, along with extensive production facilities in Taiwan and China.

Later Developments

In 2010 Danaher merged its various tool operations with those of Cooper Industries, another major conglomerate, to form the Apex Tool Group as a 50 percent joint venture. The Apex Tool Group currently operates as a private company.

More information on the history and development of Armstrong used to be available from the www.armstrongtools.com [External Link] web site, but the corporate overlords at Apex have recently deprecated Armstrong in favor of GearWrench.

Patents

Armstrong was a highly innovative organization from its beginning, and received (or licensed) many patents over the years. Their early catalogs even include a list of patent dates in the front, a thoughtful addition that would have been more useful if the patent numbers had been included as well.

Trademarks

Armstrong registered a number of trademarks, including the well-known Strong-Arm logo, the Armstrong name, and "Armaloy", their trademark for alloy-steel tools.

Tool Identification

Armstrong tools are generally easy to identify and are typically marked with the Armstrong name or trademarked logo.

Some early tools may be marked only with the A-Triangle logo, such as the Armstrong 903 Structural Wrench shown in a later figure.

A-Triangle Marking

Fig. 5B. A-Triangle Logo.

Early tools may be marked with symbol consisting of an "A" within a triangle, referred to here as the A-Triangle logo.

Fig. 5B shows the A-Triangle logo forged into a tool.

Unlike the Strong-Arm logo in the next figure, the A-Triangle logo is not known to have been registered as a trademark.

Strong-Arm Marking

In 1914 Armstrong registered the "Strong-Arm" trademark with an image showing a muscular arm holding a hammer, with the text "Strong" across the bottom.

Fig. 5C. Strong-Arm Logo from Trademark #95,975.

Manufacturing Dates

Armstrong is not known to have used any kind of a date code marking for its tools. Without such markings, any estimation of manufacturing dates will have to be based on other information, such as the design or style, patents, trademarks, finish, and so on.

Probably the most important date marker for Armstrong tools is the "Armaloy" trademark, registered with its first use in late 1946 and (presumably) marked on alloy-steel tools shortly after that. In this article we'll assume a manufacturing date of 1947 or later for Armaloy-marked tools.

Another useful indication of the manufacturing date follows from the 1978 introduction of a new product numbering system. The new system assigned a five digit model number to all tools, with part of the number indicating a category for the tool and the final digits typically encoding the size. The new model numbers were first used in Armstrong catalog 880 of 1978, and that catalog includes a cross-reference table of old and new numbers.

The following observations and events may be helpful in estimating the manufacturing date for some tools.

• A-Triangle Marking. Early Armstrong tools were marked with an A-Triangle forge mark. This mark still appeared on illustrations of carbon-steel wrenches from catalogs in the 1920s. We're uncertain of whether this was registered as a trademark.

• Early Armstrong Face Marking. Early Armstrong wrenches were stamped with "Armstrong Bros. Tool Co." and "Chicago U.S.A." on the face, and we will refer to this as the "Early Armstrong Face Marking" in the text. This marking remained in use until late 1927, based on observations of Armstrong-Vanadium wrenches.

• Armstrong-Vanadium Marking. Alloy steel wrenches had forged-in "Armstrong-Vanadium" markings from the mid 1920s until the early 1930s.

• 40x Series Tappet Wrenches. The 40x Series of tappet wrenches with equal sizes and asymmetric offsets were introduced around 1927 as part of the Armstrong-Vanadium line. The wrenches were still listed in catalog 700-A of 1966, but price sheet L-10 of September 10, 1970 noted that they would be discontinued when stocks were depleted.

• Standard Armstrong Face Marking. Beginning around 1928 wrench faces were stamped with "Armstrong" and "Made in U.S.A." plus the Strong-Arm logo, and we will refer to this as the "Standard Armstrong Face Marking" in the text. This face marking continued until around 1970, when it was replaced by the Armstrong Shank Marking stamped on the shank (see below).

• Chrome-Vanadium Marking. The forged-in "Armstrong-Vanadium" marking was replaced by a stamped "Chrome-Vanadium" (or equivalent) marking in the early 1930s. However, the Armstrong catalogs from the 1930s continued to illustrate tools with "Armstrong-Vanadium", and some examples may have been marked with a stamped "Armstrong-Vanadium". These specific alloy markings are believed to have remained in use until around 1942, after which they were typically replaced by a generic "Alloy Steel" or equivalent.

• Drive Recesses for Sockets. Based on observations, in the 1930s Armstrong sockets were made with recesses on all four walls of the drive end. (The catalogs do not document the use of drive recesses.)

• Locking Hole for Sockets. Based on observations, from about 1940 onward Armstrong provided a single locking hole in the drive end of sockets, instead of recesses in the drive walls. The locking hole remained in production until at least the 1970s, but was eventually replaced by recesses on the drive end walls. (The catalogs do not document the use of drilled locking holes, except on certain bit sockets and impact sockets.)

• Alloy Steel Marking. In Catalog 39b Armstrong changed the steel specification for sockets and drive tools to "Alloy Steel" from the prior "Chrome Vanadium Steel". This was the second of the interim wartime-era catalogs and was likely published around 1944. It's likely that the actual tool markings were changed before the catalog publication, due to wartime material shortages, so an estimate of 1942 for the beginning of this marking is probably reasonable. Since Armstrong began using the "Armaloy" trademark for alloy tools in late 1946, the "Alloy Steel" marking likely indicates production in 1942-1946.

• Hi-Tensile Marking. This marking is believed to have been first used during the 1942-1945 war years to indicate the substitution of high tensile strength steel where a chrome vanadium alloy would normally have been used. Armstrong later used "Hi-Tensile" or "Hi-Ten" for its carbon steel tool line, but this usage can be distinguished by the model numbers.

• Armaloy Trademark. Marked on alloy steel tools, first used in late 1946. The use of the "Armaloy" marking is believed to have continued into the 1990s, but was discontinued during the Danaher era.

• Plain Extensions (No Rotating Grip). By catalog S-48 of 1948 extensions were only available with a plain shank, and the model numbers were marked with a "P" suffix. Armstrong had previously supplied extensions with rotating grips from the 1930s through the mid 1940s.

• Wide-Groove Style for Sockets. By catalog S-48 of 1948 sockets were being made with a single wide groove at the base, replacing the earlier knurled band. The wide-groove style remained in use until approximately 1970.

• Extra-Long Combination Wrenches. By catalog 700 of 1961 Armstrong was offering extra-long combination wrenches, with 24 sizes ranging from model 1160L (3/8) up to 1190L (2 inches). Standard-length combination wrenches remained available in a reduced range of sizes from model 1157 (7/32) up to 1167 (7/8).

• Armstrong Shank Marking. By around 1970 the Standard Armstrong Face Marking (see above) had been discontinued and was replaced by "Armstrong - U.S.A. - Armaloy" stamped on the shank. We will refer to this as the "Armstrong Shank Marking" in the text.

  This change is not documented in the catalogs, but the date was estimated by observations of Long-Series Combination Wrenches made between 1961 and 1978. The examples in our modest collection of these wrenches are evenly split between the older face markings and newer shank markings, suggesting that the change occurred around 1970, the midpoint of the period.

• Narrow-Groove Style for Sockets. Sockets were made with a single narrow groove at the base beginning around 1970. Note though that 3/4-drive and 1 inch drive sockets continued to use the Wide-Groove style, according to the catalog illustrations.

• Drive-End Recesses for Sockets. Armstrong began using recesses on the drive end of sockets sometime in the 1970s or later, replacing the locking holes used up to that time. Examples are known of narrow-groove style sockets with drive-end recesses.

• Five-Digit Model Number System. In 1978 Armstrong switched to a five-digit model numbering system, first published in catalog 880.

• Double-Groove Style for Sockets. Sockets were made with a two narrow grooves at the base beginning sometime after 1978.

References and Resources

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

Armstrong Bros. Historical Brochure

An interesting brochure about Armstrong's History [External Link] is available (as a PDF) from a web site maintained by the Armstrong family. It's a little heavy on biography and light on technical details for our taste, but we did learn some interesting facts. We're currently (2022) going through this document to help fill in some of the gaps in our history section, and will reference the document as "ABHB" in the text.

The Armstrong web site doesn't have any contact information, but if anyone from the Armstrong family happens to read this, we would be interested in asking some questions via email.

Catalog Coverage

Our current catalog resources are summarized in the table below.

Armstrong tools were distributed by many industrial supply companies, and the catalogs from these suppliers may contain helpful information on Armstrong products. We'll add references to some of these as time permits.

Carbon Steel Tools

Carbon steel was the dominant material for toolmaking until around the mid 1920s, when various alloy steels came into general use.

Early Production

No. 2 7/16 Toolpost Wrench

Fig. 6. Armstrong No. 2 7/16 Toolpost Wrench, with Inset for Back Side Detail, ca. 1900-1920.

Fig. 6 shows an early Armstrong No. 2 7/16 toolpost wrench, marked with "Armstrong" forged into the shank, with "No. 2" forged into the back side.

The overall length is 5.0 inches, and the finish is plain steel.

No. 5 7/8 Toolpost Wrench

Fig. 7. Armstrong No. 5 7/8 Toolpost Wrench, with Inset for Back Side, ca. Early to Mid 1920s.

Fig. 7 shows an early Armstrong No. 5 7/8 toolpost wrench, stamped with "Armstrong Bros. Tool Co." and "Chicago, U.S.A." plus the model number on the face, with "1/2 NUT" on the back side.

The shank is also marked with the Strong-Arm logo forged into the front, with "5" forged into the back side.

The overall length is 8.1 inches, and the finish is plain steel.

The back side face marking is a reference to the older U.S.S. size convention for the 7/8 opening.

23A 3/8x7/16 Open-End Wrench

Fig. 8. Armstrong 23A 3/8x7/16 Open-End Wrench, with Inset for Back Side, ca. Early 1920s.

Fig. 8 shows an early Armstrong 23A 3/8x7/16 open-end wrench, stamped "Armstrong" and "Chicago, U.S.A." on the face, with the A-Triangle logo forged into the shank. The back side faces are stamped with the opening sizes as "1/4 CAP" and "3/16 CAP", references to the older Hex Capscrew size convention.

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

1623-C 7/16x9/16 Check-Nut Wrench

Fig. 9. Armstrong 1623-C 7/16x1/2 Check-Nut Wrench, with Inset for Back Side, ca. Early 1920s.

Fig. 9 shows an early Armstrong 1623-C 7/16x1/2 check-nut wrench, stamped "Armstrong Bros. Tool Co." and "Chicago, U.S.A." on the face, with the A-Triangle logo forged into the shank. The back side faces are stamped with the opening sizes as "5/16 S.A.E." and "1/4 S.A.E.", references to the older S.A.E. size convention.

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

The wrench is listed in the automotive section of the 1921 Armstrong catalog.

629C 3/4x7/8 Check-Nut Wrench

Fig. 10. Armstrong 629C 3/4x7/8 Check-Nut Wrench, with Inset for Back Side Detail.

Fig. 10 shows an Armstrong 629C 3/4x7/8 open-end check-nut (thin) wrench, marked "Armstrong Chicago U.S.A." on the face, with a forged-in A-Triangle logo on the shank. The overall length is 6.5 inches.

The inset shows the back side markings, with the model number "629" in raised letters and "C" stamped into the shank.

The mix of forged-in and stamped markings probably indicates that one forged blank could be used to make several wrench models.

661D 5/16x3/8 S-Shaped Wrench

Fig. 11. Armstrong 661D 5/16x3/8 S-Shaped Wrench, with Inset for Back Side Detail, ca. Late 1920s.

Fig. 11 shows an Armstrong 661D 5/16x3/8 S-shaped open-end wrench, marked with the A-Triangle logo forged into the shank, with the model number forged into the back side.

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

The Armstrong catalog lists this model for use with hex capscrew sizes 1/8 and 3/16, corresponding to the fractional opening sizes 5/16 and 3/8, as stamped on the wrench faces. The use of A-Triangle logo with fractional size markings suggests production in the late 1920s.

807 1-1/16 Single-Box Wrench

Fig. 12. Armstrong 807 1-1/16 Single-Box Wrench, with Inset for Back Side Detail.

Fig. 12 shows an early Armstrong 807 1-1/16 hex single-box wrench, marked with the model number forged into the shank, and with the A-Triangle logo forged into the back side.

The overall length is 9.3 inches, and the finish is plain steel.

903 11/16 Single-Open Structural Wrench

Fig. 13. Armstrong 903 11/16 Single-Open Structural Wrench, with Inset for Side View, ca. Early to Mid 1920s.

Fig. 13 shows an early Armstrong 903 11/16 open-end structural wrench, marked with the model number and A-Triangle logo forged into the shank, and stamped "Hardened" on top.

The overall length is 8.9 inches, although part of the pointed handle appears to have been broken off. (The 1923 catalog specified a length of 9.5 inches.) The finish is plain steel.

The opening is stamped "3/8 NUT", a reference to the older U.S.S. size convention. The 1923 Armstrong catalog noted that this wrench was sized for "rough nuts", with the milled opening 1/32 oversize.

Later Carbon-Steel Tools

Armstrong continued to produce certain tools in carbon steel models even after the widespread adoption of alloy steels, for applications where the greater strength (but higher cost) of alloy steel was not needed.

31 25/32x7/8 Open-End Wrench

Fig. 14. Armstrong 31 25/32x7/8 Open-End Wrench, with Inset for Side View.

Fig. 14 shows an Armstrong 31 25/32x7/8 open-end wrench, stamped on the face with "Armstrong" and "Made in U.S.A." with the Strong-Arm logo.

The overall length is 9.4 inches, and the finish is gray paint with polished faces.

5B782 (Caterpillar) 9/16x5/8 Open-End Wrench

Fig. 15. Armstrong 5B782 9/16x5/8 Open-End Wrench.

Fig. 15 shows an Armstrong 5B782 9/16x5/8 open-end wrench, stamped "Made in U.S.A." with the Strong-Arm logo on the face.

The overall length is 6.6 inches, and the finish is plain steel with traces of black paint,

Several sources have suggested that open-end wrenches in the 5B78x model series were made for Caterpillar, so this wrench has been provisionally identified as production for Caterpillar.

Similar wrenches were also produced by Billings and can be seen as the Billings 5B784 Wrench and Billings 5B785 Wrench.

5B786 (Caterpillar) 1-1/16x1-1/8 Open-End Wrench

Fig. 16. Armstrong 5B786 1-1/16x1-1/8 Open-End Wrench, with Inset for Marking Detail.

Fig. 16 shows an Armstrong 5B786 1-1/16x1-1/8 open-end wrench, stamped "Made in U.S.A." with the Strong-Arm logo on the face.

The overall length is 11.7 inches, and the finish is plain steel with traces of black paint,

Several sources have suggested that open-end wrenches in the 5B78x model series were made for Caterpillar, so this wrench has been provisionally identified as production for Caterpillar.

624-A 7/16x9/16 Check-Nut Wrench

Fig. 17. Armstrong 624-A 7/16x9/16 Check-Nut Wrench.

637 1-1/16x1-1/4 Check-Nut Wrench

Fig. 18. Armstrong 637 1-1/16x1-1/4 Check-Nut Wrench.

Fig. 18 shows a later checknut wrench, an Armstrong 637 1-1/16 by 1-1/4 thin open-end wrench, stamped on the face with "Armstrong" and "Made in U.S.A." with the Strong-Arm logo.

The overall length is 10.1 inches, and the finish is gray paint with polished faces.

607-A 1-1/8 Single-Open Check-Nut Wrench

Fig. 19. Armstrong 607-A 1-1/8 Single-Open Check-Nut Wrench.

Fig. 19 shows an Armstrong 607-A 1-1/8 single-open check-nut wrench, stamped "Armstrong" and "Made in U.S.A." with the Strong-Arm logo on the face. The shank is stamped with the model number and also has a forged-in Strong-Arm logo, visible at the left.

The overall length is 8.5 inches, and the finish is gray paint with polished faces.

661G 3/8x1/2 S-Shaped Open-End Wrench

Fig. 20. Armstrong 661G 3/8x1/2 S-Shaped Open-End Wrench.

Fig. 20 shows an Armstrong 661G 3/8x1/2 S-shaped open-end wrench, stamped on the face with "Armstrong" and "Made in U.S.A." with the Strong-Arm logo.

The overall length is 4.0 inches. The original finish was black paint, but most of the paint has been worn off.

This wrench is listed in the catalogs as a heavy-duty model for hex-head cap screws.

204-A 3/4 Single-Open Construction Wrench

Fig. 21. Armstrong 204-A 3/4 Single-Open Construction Wrench, with Inset for Back Side, ca. Mid 1940s to 1950s.

Fig. 21 shows an Armstrong 204-A 3/4 single-open construction wrench, stamped with the fractional size and model number followed by "Hardened" on the shank, and with the Strong-Arm logo forged into the shank. The back side is marked with "Armstrong" and "U.S.A." forged into the shank.

The overall length is 11.4 inches, and the finish is plain steel.

This model was listed in the 1948 catalog as a "Hi-Ten" construction wrench.