Diamond Calk Horseshoe Company

Table of Contents

• Introduction
• Adjustable Wrenches
• Pliers and Other Tools
• References and Resources
• What's New (Last Updated Mar. 10, 2008)
  Recent changes to this page:

  • 03/10/2008: Added Diamond SL56 Lineman's Pliers.
  • 12/10/2007: Updated catalog resources.
  • 11/09/2007: Minor reorganization, added a Diamond 12 Inch Adjustable Wrench.
  • 04/14/2007: Added a Diamond Diamalloy 6 Inch Adjustable Wrench and Blue Point HL112P Groove-Joint Pliers.
  • 04/13/2007: Added Diamond HL112 Groove-Joint Pliers.
  • 04/03/2007: Moved to separate page.
  • 03/30/2007: Added Diamond HL18 Groove-Joint Pliers.
  • 03/26/2007: Added a Diamond 6 Inch Adjustable Wrench.
  • 03/11/2007: Added Diamond SN56 Needlenose Pliers.
  • 02/22/2007: Added Diamond S56 Diagonal Cutters.
  • 02/20/2007: Added a Diamond 10 Inch Wide Adjustable Wrench.
  • 01/22/2007: Added Diamond DH-18 "Handyboy" Pliers.
  • 12/13/2006: Added a Diamond Diamalloy Adjustable Wrench.
  • 10/10/2006: Added a Diamond Diamalloy 12 Inch Adjustable Wrench.
  • 09/30/2006: Added a Diamond 4 Inch Adjustable Wrench.
  • 07/04/2006: Added Diamond H16 Slip-Joint Pliers.

Introduction

Company History

The Diamond Calk Horseshoe Company was founded in 1908 by Arthur Swanstrom and operated in Duluth, Minnesota. As the name suggests, the company made 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.

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.

In the late 1950s or early 1960s the company changed its name to Diamond Tool and Horseshoe, and tools produced after this were marked with the new company name. Based on trademark records, the name change was definitely in place by 1963.

By 1983 Diamond Tool had become a subsidiary of 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

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 filed the trademark registration in 1963. (By 1963 the company name had changed to "Diamond Tool and Horseshoe".)

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.

Diamond 4 Inch Adjustable Wrench

Fig. 1. Diamond Calk Horseshoe 4 Inch Adjustable Wrench, with Inset for Reverse Detail.

Fig. 1 shows an early 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.

Diamond 6 Inch Adjustable Wrench with Broached Opening

Our next figure is another early Diamond adjustable wrench, but with an unusual broached opening in the handle.

Fig. 2. Diamond 6 Inch Adjustable Wrench, with Insets for Side View and Marking Detail.

Fig. 2 shows a Diamond 6 inch adjustable wrench, marked "Tool-Steel Drop-Forged" and "Made in U.S.A." with the Diamond logo on the front, and with "Diamond Calk Horseshoe Co." and "Duluth, Minn." on the reverse. This wrench is not marked with the Diamond-Horseshoe logo, possibly due to insufficient space after the size marking for the handle opening was added.

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 handle has a 1/2 inch double-hex broached opening at the end, a feature also seen on J.P. Danielson "Bet'R-Grip" wrenches from the 1930s. Currently we're unsure of when the broached-handle models were offered by Diamond. The Diamond wrenches illustrated in the Snap-On catalogs from 1927 and 1937 do not show a broached handle opening, and a Diamond catalog from the late 1940s also does not show broached openings.

Diamond 12 Inch Adjustable Wrench

Fig. 3. Diamond 12 Inch Adjustable Wrench, with Insets for Side View and Marking Detail, ca. 1963+.

Fig. 3 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.

The Diamalloy Era

In 1931 Diamond registered the "Diamalloy" trademark for their line of alloy-steel tools.

Diamalloy 6 Inch Adjustable Wrench

Fig. 4. Diamond Diamalloy 6 Inch Adjustable Wrench, with Inset for Reverse Detail.

Fig. 4 shows a later Diamond Diamalloy 6 inch adjustable wrench, marked "Forged Steel" and "Made in U.S.A." with the Diamalloy logo on the front. The reverse is marked "Diamond Calk Horseshoe Co." and "Duluth, Minn." with the Diamond-Horseshoe logo.

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 10 Inch Adjustable Wrench

Fig. 5. Diamond Diamalloy 10 Inch Adjustable Wrench, with Inset for Reverse.

Our next example is shown in Fig. 5, a Diamalloy 10 inch adjustable wrench marked "Forged Steel" and "Made in U.S.A." with the Diamalloy logo, all in raised letters. The opposite side is marked "Diamond Calk Horseshoe Co." and "Duluth, Minn." with the Diamond-Horseshoe logo.

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

Fig. 6. Diamond "Diamalloy" 12 Inch Adjustable Wrench, with Inset for Reverse.

Fig. 6 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.

Diamalloy 8 Inch Adjustable Wrench

Fig. 7. Diamond Diamalloy 8 Inch Adjustable Wrench, with Inset for Reverse, ca. 1963+.

Fig. 7 shows a later adjustable wrench, a Diamond 8 inch model marked with the "Diamalloy" logo, "Alloy Steel", and "Forged in U.S.A." in raised letters. The opposite side is marked "Diamond Tool and Horseshoe Co." and "Duluth, Minn.", along 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.

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.

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

Fig. 8. Diamond 10 Inch Wide Opening Adjustable Wrench.

Fig. 8 shows a Diamond 10 inch wide opening adjustable wrench, marked with the Diamond logo and "Wide Opening", with "U.S.A." on the reverse.

The overall length is 10.0 inches, and 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 finish is chrome plating with polished faces.

The maximum head thickness was measured at 0.57 inches.

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 Diamalloy H16 Slip-Joint 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.

Fig. 9. Diamond Diamalloy H16 Slip-Joint Combination Pliers, with Inset for Handle Pattern.

Fig. 9 shows a pair of Diamalloy H16 slip-joint combination pliers, marked "Duluth, USA" with the Diamond-Horseshoe logo. The handle also shows a forged-in "Forged in U.S.A." marking.

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

Diamond Diamalloy DH18 "Handyboy" Combination Tool

Fig. 10. Diamond Diamalloy DH18 Slip-Joint "Handyboy" Pliers.

Fig. 10 shows an example of the popular "Handyboy" combination tool, a pair of Diamond DH18 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.

Diamond Diamalloy SL56 6 Inch Lineman's Pliers

Fig. 11A. Diamond Diamalloy SL56 6 Inch Lineman's Pliers, with Inset for Side View.

Fig. 11A 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.

Diamond Diamalloy SN56 6 Inch Needlenose Pliers with Side Cutters

Fig. 11B. Diamond Diamalloy SN56 6 Inch Needlenose Pliers, with Inset for Side View.

Fig. 11B 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.

Diamond Diamalloy S56 6 Inch Diagonal Cutters

Fig. 12. Diamond Diamalloy S56 6 Inch Diagonal Cutters, with Inset for Side View.

Fig. 12 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 HL18 "Groove-Joint" Tongue-and-Groove Pliers

Fig. 13. Diamond Diamalloy HL18 "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 13 shows a pair of Diamalloy HL18 tongue-and-groove pliers, marked "Groove-Joint" and "Duluth, U.S.A." with the Diamond-Horseshoe logo.

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

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

Fig. 14. Diamond Diamalloy HL112 "Groove-Joint" Tongue-and-Groove Pliers.

Fig. 14 shows a pair of Diamalloy HL112 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.

Blue Point HL112P Tongue-and-Groove Pliers

In later years 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 pliers made by Diamond for Blue Point.

Fig. 15. Blue Point HL112P Tongue-and-Groove Pliers, with Inset for Construction Detail, ca. 1973+.

Fig. 15 shows a pair of Blue Point HL112P tongue-and-groove pliers, marked "Made in U.S.A." with a "Pat. 3730664" 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.

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.

References and Resources

Photographs and observations of particular tools are based on items in my personal 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.

Diamond tools were available through various industrial suppliers, and the catalogs from these companies may have useful information for Diamond products.

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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