Bonney Forge & Tool Works Manufacturer's Date Codes

What is the meaning of the two-letter code cast/forged into on Bonney wrenches?  These marks appear on most Bonney wrenches of the period roughly covering the period from the 1930s to the mid 1970s. These codes are mentioned in  the first Bonney Tools Page of the excellent and extensive Alloy Artifacts Web Site, but the meaning of the code was not generally known.

Note: Alloy-Artifacts.com has published an update to the code interpretation below. See that site for details. He correctly noticed that the year codes ran only from M through Z, showing the year interpretation on this page to be incorrect. A revised decoding scheme will be presented here after giving some thought to the matter (and after my deflated ego recovers ;-) ,
(added June 1, 2008.)

Results Summary

The two-letter code indicates a month and year. This probably is the date when the casting or forging tooling, used to make the wrenches, was placed into service. This type of two-letter date code also is/was used by Sansin, Shimano, and SunTour on their bicycling components. See the Component Dates page on Vintage-Trek.com for details. The Alloy Artifacts web site describes tool dating codes used by Snap-on, Williams, and Wright.

The first letter ranges from A through L, a total of twelve letters. This first letter indicates the month;. where A = January, B = February and so on. The second letter indicates year.  The problem in understanding the year is determining the starting date of the lettering system (what year is A?). After study of available Bonney wrenches, the original "A" year was determined to be 1924 with a possible error estimated at ± 2 years.

Table 1 - First Letter is the Month Code

Table 2 - Second Letter is the Year Code

Analysis Detail

In the absence of other information, the date the company was established is often a reasonable starting point. According to the Alloy-Artifacts.com (AA) web site, The Bonney Vise & Tool Works was established in 1877. The name was changed to Bonney Forge and Tool Works in 1921. If one uses 1877 is the first A year code, then A repeats in 1903, 1929 and 1955. If 1921 is the first A year, then A repeats in 1947. If one uses the 1877 starting date, a given year code will be eight years earlier relative to a 1921 starting date.

To verify the starting (A) year, one must have a coded tool with a known manufacturing date or a number of similar tools with a range over which they were produced. The tools produced during World War II (WWII) typically have characteristics that tie them to that period. For example, the Alloy-Artifacts web site states a Model 2894 wrench marked KT is dated at 1942-43 based on the WWII style finish. The code on the tool, KT, is November of 1940 (if A=1921) or 1948 (if A=1877). Neither of these years is close to the 1942-43 Alloy-Artifacts date. A better match is if A=1924 then T is 1943.

Other Alloy Artifact dates given for tools with WWII characteristics are:

• AA "Fig. 80. Bonney 2805B Bonaloy 1/2x19/32 Offset Box-End Wrench, with Insets for Side View and Reverse Detail, ca. 1944-1945." The date code, IU (assuming A=1924), indicates a manufacturing date September, 1944.
• AA "Fig. 85. Bonney 2893B Bonaloy 3/4x7/8 Box-End Wrench, with Inset for Reverse Detail, ca. 1944-1945". . The date code, AV (assuming A=1924), indicates a date of January, 1945.
• AA "Fig. 81. Bonney 2807A Bonaloy 5/8x11/16 Offset Box-End Wrench, with Insets for Side and Reverse, ca. 1944-1945." The date code, LV (assuming A=1924), indicates a date of December 1945.

The 1924 date for "A" stands up well for other wrench codes listed in Table 3:

• The trademark for Bonney CV and Chrome-Vanadium markings, according to Alloy Artifacts, was registered in 1925 and was phased out in the early 40s. In Table 3 the dates for these markings range from 1937 to 1947, comprising a total of 42 tools.
• According to Alloy Artifacts, the Bonaloy marking was first used in 1939, in use until 1950s. The dates for Bonaloy markings, in Table 3, range from 1943 to 1948, comprising a total of 17 tools.
• Zenel, According to Alloy Artifacts, was used on Bonney tools from 1933 (or earlier) up to about 1950. In Table 3, the range of the eleven Zenel-marked wrenches is 1937 to 1949.

Table 3 below lists over 100 Bonney wrenches that are marked with the cast-in two letter code. This information was extracted from the information on the Bonney pages in the Alloy Artifacts web site, from pictures of tools on Ebay.com and from my own small collection. The owner or source is listed in the fifth column where "AA" is Alloy Artifacts and "Skip" is from my collection.

Table 3 - Bonney Tools Marked with Two Letter Date Code

Interestingly, the last year date code in Figure 3 is a Z (indicating 1975). Could the Bonney folks have simply decided the date code should end at Z rather than starting again at A? If you have any newer tools with a date code beyond Z, please contact me: skip@skipechert.com.

Dots on Bonney Tools.

Many Bonney tools have raised dots cast or forged into the handle of the tool. Table 3 includes the number of these dots found on each of the tools. The number of dots on the tools range from zero to seven. The dots are not placed with precision; the spacing between dots varies as does the depth height and width of the dots.

What do the dots signify? I believe they may indicate the number of times new production tooling was made from the master tooling. The first production tooling has no dot. Before each subsequent production tooling was made, a dimple was made in the master, resulting in a raised dot in the tool. . The dimple could have been made simply with a hammer and a pointed drift. The more use the production tooling got, the more often new tooling had to be made.

Here are a couple of ways to help support or disprove this concept.

• Ask an experienced tool and die maker.
• More dots should mean the line of tools has been used over a long period of time. No dot means the tool was made early in the lifecycle of the tool line. The most dots would be at the end of the tool line.
• If the dots were made on the master, then the tool with one dot should have the dot in the same position as on the tools with more dots.

I am working to sort this out. Your help would be appreciated.

Comments Corrections and Suggestions Sought

If you have comments, corrections or suggestions about the above information please contact me, Skip Echert, at Skip@skipechert.com.

Copyright 2008, Skip Echert Web Associates, all rights reserved.