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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.)

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.

[1922 Advertisement for Diamond Adjustable Wrenches]
Advertisement for Diamond Adjustable Wrenches, 1922. [External Link]

An example of an early Diamond adjustable wrench can be seen in the illustration at the left, part of an advertisement placed in a 1922 issue of The Horseshoer's Magazine.

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.

In 1952 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, rather than being cut by machine tools, and are believed to have been based on a patent licensed from Utica Tools. An example of the new tongue-and-groove pliers can be seen in the October 1959 issue of Popular Mechanics, in an advertisement for 12 Inch Groove Joint Pliers on page 307.

In 1958 (or possibly late 1957) 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.

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

Table 1A. Diamond Calk Horseshoe Company: Issued and Licensed Patents
Patent No.InventorFiledIssuedDescriptionExamples
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  
2,818,758 J.E. Swanstrom et al03/27/195601/07/1958Spring-Loaded Pliers  
2,849,908 J.E. Swanstrom et al08/06/195709/02/1958Adjustable Wrench with Locking Mechanism  
3,304,817 J.E. Swanstrom et al02/26/196502/21/1967Chain Pipe Wrench  
3,404,457 J.E. Swanstrom, Sr.07/26/196610/08/1968Alloy 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 1952 Diamond began using the "Groove-Joint" trademark 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".)

Table 1B. Diamond Calk Horseshoe: Registered Trademarks
Text Mark First Use Date Filed Date Issued Registration Notes
[Diamond Horseshoe Logo] August, 1908 03/11/1921 05/29/1923 168,676 Horseshoe and diamond with calk in the center. Renewed in 1943.
Diamond [Diamond Logo] 1919 10/24/1925 02/16/1926 209,074 Renewed in 1946
Diamalloy [Diamond Logo] Late 1931 12/14/1942 05/18/1943 401,456  
Diamalloy [Diamond Logo] Late 1931 09/08/1952 02/16/1954 585,695 Coverage extended to tinner's snips and heavy-duty nippers
Groove-Joint 06/04/1952 02/04/1963 07/07/1964 772,762 Tongue-and-Groove Pliers

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.

  • Duluth Minn U.S.A. Marking. Adjustable wrenches with the location marked as "Duluth Minn U.S.A." appear to represent the company's earliest production, probably from the 1920s. Later wrenches were marked "Duluth Minn" with a separate "Made in U.S.A." marking.
  • Plain (Non-Reinforced) Hanging Hole. Diamond's early adjustable wrenches were made with a plain hanging hole without a ridge around it. Based on a review of Snap-on catalogs, the plain hole continued in production until at least 1939.
  • Diamalloy Trademark. The Diamalloy trademark was first used in late 1931.
  • Reinforced Hanging Hole. Later adjustable wrenches (in sizes 12 inches and under) were made with a reinforcing ridge around the hanging hole. The exact date of the change is not known, but it probably went into effect in the early 1940s. Currently it's uncertain whether this observation applies to wrenches larger than 12 inches.
  • Broached Hanging Hole. At some point Diamond began offering adjustable wrenches with a broached (double-hex) hanging hole, similar to the models made by the J.P. Danielson company. These appear to have been available only for a relatively brief span, probably in the early to mid 1940s. (A Diamond catalog from 1948 does not show broached holes.)
  • "Groove-Joint" Pliers. In 1952 Diamond began offering tongue-and-groove pliers under the "Groove-Joint" brand. The known examples have forged ribs and Diamond is believed to have licensed the patent for this construction from Utica Drop Forge.
  • Diamond Tool and Horseshoe Name. In 1958 (or possibly late 1957) the company changed its name from "Diamond Calk Horseshoe" to "Diamond Tool and Horseshoe". Several published references to the new name have been found with 1958 dates.
  • Extended Panel for Adjustable Wrenches. By 1983 adjustable wrenches were being made with the depressed panel extending all the way to the adjusting knurl, to provide easier access.
  • "No Hammering" Marking. By 1983 adjustable wrenches included a "No Hammering" warning forged into the shank.

Calk Wrenches and Other Early Tools

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. 1. Early Diamond 9/16 Calk Wrench, with Inset for Reverse Detail, ca. 1919 to Mid 1920s.

Fig. 1 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 reverse. 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.


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. 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.


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.


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. 2. Diamond "Tool Steel" 6 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Early to Mid 1920s.

Fig. 2 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 reverse. 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. 3. Diamond "Tool Steel" 6 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Early to Mid 1920s.

Fig. 3 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 reverse. 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. 4. Diamond "Tool Steel" 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Early to Mid 1920s.

Fig. 4 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 reverse. 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. 5. Diamond "Tool Steel" 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Early to Mid 1920s.

Fig. 5 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 reverse. 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. 6. Diamond "Tool Steel" 12 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Mid to Late 1920s.

Fig. 6 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 reverse.

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.


"Tool Steel" Wrenches


"Tool Steel" 4 Inch Adjustable Wrench

[Diamond Tool Steel 4 Inch Adjustable Wrench]
Fig. 7. Diamond "Tool Steel" 4 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. Late 1920s to 1930s.

Fig. 7 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 reverse 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. 8. Diamond "Tool Steel" 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Early 1930s.

Fig. 8 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 reverse.

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 reverse. 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. 9. Diamond "Tool Steel" 10 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1930s.

Fig. 9 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 reverse.

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. 10. Diamond "Tool Steel" 10 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1930s.

Fig. 10 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 reverse.

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.


Later "Tool Steel" 12 Inch Adjustable Wrench

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

[Diamond 12 Inch Adjustable Wrench]
Fig. 11. Diamond "Tool Steel" 12 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s to 1958.

Fig. 11 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 reverse.

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.


The Diamalloy Era

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

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


Early Diamalloy 4 Inch Adjustable Wrench

[Diamond Early Diamalloy 4 Inch Adjustable Wrench]
Fig. 12. Diamond Early "Diamalloy" 4 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1930s.

Fig. 12 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 reverse. 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.

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. 13. Diamond Early "Diamalloy" 6 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1930s.

Fig. 13 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 reverse. 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. 14. Diamond Early "Diamalloy" 10 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1930s.

Fig. 14 shows an early Diamalloy 10 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front. The reverse is marked with "Diamond Calk Horseshoe Co." and "Duluth, Minn." plus the Diamond-Horseshoe logo forged into the reverse. 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.


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. 15. Diamond "Diamalloy" 4 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1942-1945.

Fig. 15 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 reverse. 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. 16. Diamond "Diamalloy" 4 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. 1945-1958.

Fig. 16 shows a Diamond Diamalloy 4 inch adjustable wrench, marked with "Diamalloy Steel" and "Made in U.S.A." forged into the front. The reverse 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. 17. Diamond "Diamalloy" 6 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. 1945-1958.

Fig. 17 shows a Diamond Diamalloy 6 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the front. The reverse 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. 18. Diamond "Diamalloy" 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1942-1945.

Fig. 18 shows an earlier Diamalloy 8 inch adjustable wrench, marked with "Forged Diamalloy Steel" and "Made in U.S.A." forged into the shank. The reverse 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. 19. Diamond "Diamalloy" 8 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. 1945-1958.

Fig. 19 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. 20. Diamond "Diamalloy" 10 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1942-1945.

Fig. 20 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 reverse. 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. 21. Diamond "Diamalloy" 10 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. 1945-1958.

Fig. 21 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 reverse. 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. 22. Diamond "Diamalloy" 12 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. 1942-1945.

Fig. 22 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. 23. Diamond "Diamalloy" 15 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1942-1945.

Fig. 23 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 reverse.

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. 24. Diamond "Diamalloy" 15 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s to 1958.

Fig. 24 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 reverse.

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. 25. Diamond "Tool Steel" 10-12 Inch Double-Ended Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Mid to Late 1920s.

Fig. 25 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 reverse. 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 reverse, 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. 26. Diamond "Diamalloy" 6-8 Inch Double-Ended Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1942-1945.

Fig. 26 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 reverse. 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.


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 not known whether the new feature was present on all wrench models, or just as an optional feature.

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. 27. Diamond 6 Inch Adjustable Wrench, with Insets for Side View and Marking Detail, ca. 1940s.

Fig. 27 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 reverse. 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. 28. Diamond 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. Early 1940s.

Fig. 28 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 reverse. 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. 29. Diamond 10 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1942-1945.

Fig. 29 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 reverse. 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.


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. 30. Diamond Diamalloy 4 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s.

Fig. 30 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 reverse. 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. 31. Diamond Diamalloy 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s.

Fig. 31 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 reverse. 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. 32. Diamond Diamalloy 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s.

Fig. 32 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 reverse. 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. 33. Diamond Diamalloy 12 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s.

Fig. 33 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 reverse. Both sides are also marked "12 In." for the nominal size, and the broached hole is marked "3/4" on the reverse.

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.


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. 34. Diamond 12 Inch Adjustable Wrench, with Insets for Side View and Marking Detail, ca. 1959-1982.

Fig. 34 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 reverse is 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. 35. Diamond Diamalloy 8 Inch Adjustable Wrench, with Inset for Reverse Detail, ca. 1959-1982.

Fig. 35 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.


Later Production

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. 36. Diamond 10 Inch Wide Opening Adjustable Wrench, ca. 1983+.

Fig. 36 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 reverse (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.)


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 pliers were definitely in production by 1931.


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

[Diamond K18 Motor Spec 8 Inch Combination Pliers]
Fig. 37. "Motor Spec" (Diamond) K18 8 Inch Combination Pliers, with Inset for Side View.

Fig. 37 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. 38. "Motor Spec" (Diamond) K110 10 Inch Combination Pliers, with Inset for Side View.

Fig. 38 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. 39. Diamond K36 6 Inch Combination Pliers, with Inset for Side View.

Fig. 39 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. 40. Diamond Diamalloy H16 6 Inch Combination Pliers, with Inset for Handle Pattern.

Fig. 40 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. 41. Diamond M26 6 Inch Bent Thin-Nose Combination Pliers, with Inset for Side View.

Fig. 41 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. 42. Diamond N18 8 Inch Thin-Nose Combination Pliers, with Inset for Side View.

Fig. 42 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. 43. Diamond Diamalloy KC-18 Hose Clamp Pliers, with Insets for Side View and Marking Detail.

Fig. 43 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.


Diamalloy SL56 6 Inch Lineman's Pliers

[Diamond Diamalloy SL56 6 Inch Lineman's Pliers]
Fig. 44. Diamond Diamalloy SL56 6 Inch Lineman's Pliers, with Inset for Side View.

Fig. 44 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. 45. Diamond Diamalloy SN56 6 Inch Needlenose Pliers, with Inset for Side View.

Fig. 45 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. 46. Diamond Diamalloy S56 6 Inch Diagonal Cutters, with Inset for Side View.

Fig. 46 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. 47. Diamond Diamalloy G57 7 Inch End Nippers, with Inset for Side View.

Fig. 47 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. 48. Diamond Diamalloy DH16 "Handiman" 6 Inch Combination Tool, with Insets for Marking Detail.

Fig. 48 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 reverse 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. 49. Diamond Diamalloy DH18 "Handyboy" 8 Inch Combination Tool.

Fig. 49 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 Diamond introduced a line of tongue-and-groove pliers under the "Groove-Joint" trademark.


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

[Diamond Diamalloy HL18 8 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 50. Diamond Diamalloy HL18 8 Inch "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 50 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 HL19-1/2 9.5 Inch "Groove-Joint" Tongue-and-Groove Pliers

[Diamond Diamalloy HL19-1/2 9.5 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 51. Diamond Diamalloy HL19-1/2 9.5 Inch "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 51 shows an early pair of Diamalloy HL19-1/2 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.


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

[Diamond Diamalloy HL112 12 Inch Groove-Joint Tongue-and-Groove Pliers]
Fig. 52. Diamond Diamalloy HL112 12 Inch "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 52 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. 53. Diamalloy HL18P 8 Inch "Groove-Joint" Tongue-and-Groove Pliers, with Insets for Construction and Marking Detail, ca. 1973+.

Fig. 53 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 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. 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.

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. 54. K.H.T. "Hickory" 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1920s.

Fig. 54 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 reverse. 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. 55. Ward's Master Quality 12 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1930s.

Fig. 55 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 reverse.

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. 56. Ward's Master Quality 8 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s.

Fig. 56 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 reverse, 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. 57. Ward's Master Quality 6 Inch Adjustable Wrench, with Insets for Side View and Reverse Detail, ca. 1940s.

Fig. 57 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 reverse.

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.


Snap-on/Blue Point


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

[Blue-Point HL112P 12 Inch Tongue-and-Groove Pliers]
Fig. 58. Blue-Point HL112P 12 Inch Tongue-and-Groove Pliers, with Inset for Construction Detail, ca. 1973+.

Fig. 58 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 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. 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.


References and Resources

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


Catalog Coverage

Currently our catalog resources for Diamond include a "Condensed Catalog Supplement 8" from 1949, catalog W-83 from 1983, and catalog No. 700 from 1986. The latter two catalogs were issued after Diamond became a subsidiary of Triangle Tool.

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.

The two later catalogs are fairly similar and offer adjustable and auto wrenches, chain wrenches, a wide variety of pliers and cutters, screwdrivers, hammers, and other tools.


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.

  • Gamble's Auto Supply 1940. The 1940 Gamble's Auto Supply & Tool catalog offered adjustable wrenches under the Gamble's and Tiger brands, with both types recognizable as Diamond production. The Gamble's brand wrenches noted the use of drop forged steel with a black finish, and the Tiger brand wrenches featured chrome alloy steel with a triple-plated chrome finish. Both models were illustrated with hexagonal gullets and double-hex broached hanging holes. Wrenches were available in sizes 4, 6, 8, 10, 12, 15, 18, and 24 inches, with the 24 inch size only in the alloy steel (Tiger) model. This is currently our only catalog reference showing broached hanging holes for Diamond wrenches.


Patent and Trademark Information

Patent information was obtained from the U.S. Patents and Trademarks Office (USPTO) web site at uspto.gov. Patent documents were obtained from sites offering free downloads, notably freepatentsonline.com.


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