Zenel Alloy Tools

In the early 1930s Bonney began using an alloy steel called Zenel and advertised it as the strongest known steel for tools. (Such claims were frequently made by tool companies of that time.) Bonney registered the Zenel brand as trademark #306,876, which was issued on October 3, 1933.

Fig. 204. Front Cover of 1933 Catalog.

The trademark application gave August 31, 1932 as the first use date, and the earliest known listing for Zenel tools is in catalog No. 33 from 1933. Since catalogs for a given calendar year would normally be printed late in the prior year, it's reasonable to assume that the Zenel tools in the main catalog would have been produced in late 1932.

Fig. 204 shows the front cover of the 1933 Bonney catalog No. 33, which notes the inclusion of Zenel wrenches in several places.

The catalog lists two pages of Zenel tools in the main section, specifically the double-open "Engineer's" wrenches and tappet wrenches. Electrical (ignition) wrenches followed in a "New Items" supplement printed in January of 1933, and combination wrenches (amusingly called "TuType") were listed in a supplement printed in May of 1933.

Box-end wrenches were not yet available in Zenel steel at this time.

The date of the "TuType" combination wrench listing is rather significant, as this is very close to the time that Plomb Tools first advertised its combination wrenches, and Plomb is generally credited with originating this popular wrench style. The Zenel "TuType" combination wrenches were actually the first of this style offered by Bonney, and followed the emerging standard of 15 degree offsets for both ends. The initial 1933 listing offered only four sizes, models 3114 (7/16), 3116 (1/2), 3118 (9/16), and 3120 (5/8).

Zenel tools were given model numbers beginning with a "3" for quick identification, as these were sold at premium prices. The open-end wrenches were given a 3xxx series (3000 plus the industry-standard number), combination wrenches were the 31xx series, and tappet wrenches were in the 34xx series. (The miniature ignition wrenches were the exception; these were assigned models beginning with an "E" or "H".)

Although we can't verify whether Zenel was really the strongest alloy steel, the available examples of Zenel tools do appear to be of very high quality. Some of the photographs below show tools used extensively to the point that the chrome plating has worn through, but the broached openings are still in nearly perfect condition.

But What Is Zenel?

For readers curious about the actual composition of Zenel steel, we used our X-ray vision (aka XRF testing) to determine the chemical makeup of the Bonney Zenel 3120 Wrench shown in a later figure. The results showed about 0.5% manganese, 0.7% chromium, 0.4% molybdenum, and an indeterminate nickel content due to remnants of the plated finish.

From these results we can conclude that Zenel was some type of chrome-moly or nickel-chrome-moly alloy steel. However, the measured chrome-moly components are somewhat different from the standard 4140 or 8740 steels often used for toolmaking — not enough chromium and too much molybdenum for 4140, and about the right chromium but too much molybdenum for 8740. Thus it's possible that Bonney was using a custom formulation of steel for its Zenel tools. More testing will need to be done to determine the composition more accurately.

Please see our article on Alloy Steel for more information on XRF testing.

Zenel Product Lifespan

The Zenel product line had a relatively short lifespan, with some selections already discontinued by as early as 1938. (By this time the tool buyer's fascination with alloy steels was apparently beginning to fade.) The most successful of the Zenel products were the tappet and open-end wrenches, which remained in production into the 1950s.

The table below shows the approximate dates of the introduction and eventual discontinuation of the various categories of Zenel products.

Zenel Tappet Wrenches

Zenel tappet wrenches were listed in the main section of the 1933 catalog, and production is presumed to have begun in late 1932.

3420 Zenel 7/16x17/32 Tappet Wrenches

The next figures show two generations of the Bonney 3420 Zenel tappet wrench.

Fig. 205. Bonney 3420 Zenel 7/16x17/32 Tappet Wrench, 1933.

Fig. 205 shows an earlier Bonney 3420 7/16x17/32 tappet wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code "JY" (not shown).

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

The "Y" year code and "Made in U.S.A." marking indicate production in 1933.

Fig. 206. Bonney 3420 Zenel 7/16x17/32 Tappet Wrench, 1947.

Fig. 206 shows a later Bonney 3420 7/16x17/32 tappet wrench, stamped "U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code "JY." (see inset).

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

The "U.S.A." face marking indicates production in the late 1940s or 1950s, and the "Y" year code indicates 1947.

3420A Zenel 7/16x1/2 Tappet Wrench

Fig. 207. Bonney 3420A Zenel 7/16x1/2 Tappet Wrench, 1947.

Fig. 207 shows a Bonney 3420A 7/16x1/2 tappet wrench, stamped "U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code "HY.." visible at the left.

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

The "Y" year code and "U.S.A." marking indicate production in 1947.

3422 Zenel 1/2x9/16 Tappet Wrench

Fig. 208. Bonney 3422 Zenel 1/2x9/16 Tappet Wrench, 1946.

Fig. 208 shows a Bonney 3422 1/2x9/16 tappet wrench, stamped "Made in U.S.A." on the face, with "Zenel" forged into the shank. The back side shank has a forged-in code "DX." (not shown).

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

The "X" year code indicates production in 1946.

3424 Zenel 5/8x11/16 Tappet Wrenches

The next two figures show examples of the Bonney 3424 Zenel wrench model.

Fig. 209. Bonney 3424 Zenel 5/8x11/16 Tappet Wrench, with Inset for Back Side Detail, 1945.

Fig. 209 shows a Bonney 3424 5/8x11/16 tappet wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank. This example still has its Zenel decal, visible on the shank at the left, and the back side shank has a forged-in code "KW" (see inset).

The overall length is 8.5 inches, and the finish is chrome plating with polished faces.

The "W" year code indicates production in 1945.

Fig. 210. Bonney 3424 Zenel 5/8x11/16 Tappet Wrench, 1945.

Fig. 210 shows a similar Bonney 3424 tappet wrench, stamped "Made in U.S.A." on the face, with "Zenel" forged into the shank.

The shank also has a forged-in code "KW." on the back (not shown).

The overall length is 8.5 inches, and the finish is chrome plating with polished faces.

The "W" year code indicates production in 1945.

Another example of this model in our collection has a forged-in code "CP....." on the back side.

3426 Zenel 3/4x7/8 Tappet Wrench

Fig. 211. Bonney 3426 Zenel 3/4x7/8 Tappet Wrench, with Inset for Back Side Detail, 1945.

Fig. 211 shows a Bonney 3426 3/4x7/8 tappet wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank.

This example still has its Zenel decal, visible on the shank at the left, and the back side has a forged-in code "KW" (see inset).

The overall length is 9.0 inches, and the finish is chrome plating with polished faces.

The "W" year code indicates production in 1945.

Zenel Open-End Wrenches

Zenel open-end "Engineer's" wrenches were listed in the main section of the 1933 catalog, and production is presumed to have begun in late 1932.

Fig. 212. 1933 Catalog Listing for Zenel Open-End Wrenches.

The scan in Fig. 212 shows the listing for Zenel open-end wrenches on page 18 of catalog No. 33 from 1933.

Individual wrenches were offered in 23 sizes, ranging from model 3721 (5/16x3/8) up to 3035 (31/32x1-1/16). In addition, two sets were available, a Z-25 set with six wrenches and a Z-26 set with eight wrenches.

Zenel wrenches were Bonney's top-of-the-line tools and sold at a premium price. For comparison, the 1934 list price for the 3731A wrench was $1.20, compared to $0.95 for the Bonney "CV" 1731A model.

3723 Zenel 3/8x7/16 Open-End Wrench, PWA Contract

Fig. 213. Bonney 3723 (PWA1401) Zenel 3/8x7/16 Open-End Wrench, with Inset for Back Side Detail, 1940.

Fig. 213 shows a Bonney Zenel 3723 3/8x7/16 open-end wrench, stamped "Made in U.S.A." on the face with "Zenel" in forged raised letters on the shank. The back side is stamped "PWA1401", indicating that this wrench was produced for Pratt-Whitney Aircraft. The shank also has a forged-in code "KR...." visible at the left.

The overall length is 4.7 inches. The original finish was chrome plating, but most has been lost due to rust.

The "R" year code and "Made in U.S.A." marking indicate production in 1940.

3723A Zenel 3/8x1/2 Open-End Wrench

Fig. 214. Bonney 3723A Zenel 3/8x1/2 Open-End Wrench, with Inset for Back Side Detail, 1947.

Fig. 214 shows a Bonney Zenel 3723A 3/8x1/2 open-end wrench, stamped "U.S.A." with the plain Bonney name on the face. The shank is marked "Zenel" in forged raised letters, with a forged-in code "CY." visible on the back side (see inset).

The overall length is 4.7 inches, and the finish is chrome plating with polished faces.

The "Y" year code and "U.S.A." face marking indicate production in 1947.

3725B Zenel 1/2x9/16 Open-End Wrenches

The next figures show several generations of the Bonney Zenel 3725B wrench.

Fig. 215. Bonney 3725B Zenel 1/2x9/16 Open-End Wrench, with Inset for Back Side Detail, 1935.

Fig. 215 shows a Bonney Zenel 3725B 1/2x9/16 open-end wrench, stamped "Made in U.S.A." with the plain Bonney name on the face. The shank is marked "Zenel" in forged raised letters, with a forged-in code "IM" visible on the back side (see inset).

The overall length is 5.7 inches, and the finish is chrome plating with polished faces.

The "Made in U.S.A." face marking and "M" year code indicate production in 1935, in the second cycle of Bonney's date code system.

Fig. 216. Bonney 3725B (PWA1113) Zenel 1/2x9/16 Open-End Wrench, with Inset for Back Side Detail, 1942.

Fig. 216 shows a Bonney Zenel 3725B 1/2x9/16 open-end wrench, stamped "Made in U.S.A." on the face. The shank is marked "Zenel" in forged raised letters with a forged-in code "GT." visible at the left, and the back side is stamped "PWA1113", indicating that this wrench was produced for Pratt-Whitney Aircraft.

The overall length is 5.5 inches, and the finish is plain steel.

The PWA marking and plain finish suggest a 1941-1945 manufacturing date, and the year code "T" indicates production in 1942.

Fig. 217. Bonney 3725B Zenel 1/2x9/16 Open-End Wrench, 1949.

Fig. 217 shows a somewhat later Bonney Zenel 3725B open-end wrench, stamped "U.S.A." on the face with "Zenel" in forged raised letters on the shank. The shank also has a forged-in code "AM.." visible at the left.

The overall length is 5.7 inches, and the finish is chrome plating with polished faces.

The "U.S.A." marking on the face would indicate production in the late 1940s onward, and the "M" year code indicates the production year as 1949.

3027C Zenel 9/16x11/16 Open-End Wrench

Fig. 218. Bonney 3027C Zenel 9/16x11/16 Open-End Wrench, with Inset for Back Side Detail, 1940.

Fig. 218 shows a Bonney Zenel 3027C 9/16x11/16 open-end wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank. The inset shows a close-up of the forged-in code "GR." on the back side shank.

The overall length is 7.0 inches. The finish is chrome plating, with some loss due to rust and pitting.

The "R" year code and "Made in U.S.A." marking indicate production in 1940.

3729 Zenel 5/8x3/4 Open-End Wrenches

The next figures show two generations of the Bonney Zenel 3729 wrench.

Fig. 219. Bonney 3729 Zenel 5/8x3/4 Open-End Wrench, 1946.

Fig. 219 shows an earlier Bonney Zenel 3729 5/8x3/4 open-end wrench, stamped "Made in U.S.A." on the face, with "Zenel" in forged raised letters on the shank. A forged-in code "DX.." is visible on the shank at the left.

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

The "X" year code indicates production in 1946.

Fig. 220. Bonney 3729 Zenel 5/8x3/4 Open-End Wrench, with Inset for Back Side Detail, 1947.

Fig. 220 shows a later Bonney Zenel 3729 open-end wrench, stamped "U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code "CY." as shown in the inset.

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

The "Y" year code and "U.S.A." marking indicate production in 1947.

3028S Zenel 5/8x25/32 Open-End Wrench

The next two figures show examples of the Bonney Zenel 3028S model.

Fig. 221. Bonney 3028S Zenel 5/8x25/32 Open-End Wrench, with Inset for Back Side Detail, 1935.

Fig. 221 shows an earlier Bonney Zenel 3028S 5/8x25/32 open-end wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code "CM..v.." as shown in the inset.

The overall length is 8.0 inches. The finish is chrome plating with extensive pitting due to rust.

The "M" year code and "Made in U.S.A." marking indicate production in 1935, the beginning of the second cycle of the Bonney date code system.

Fig. 222. Bonney 3028S Zenel 5/8x25/32 Open-End Wrench, with Inset for Back Side Detail, 1945.

Fig. 222 shows a later Bonney 3028S open-end wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code "LW." visible at the left.

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

The "W" year code and "Made in U.S.A." marking indicate production in 1945.

3731A Zenel 3/4x7/8 Open-End Wrench

Fig. 223. Bonney 3731A Zenel 3/4x7/8 Open-End Wrench, 1945.

Fig. 223 shows a Bonney Zenel 3731A 3/4x7/8 open-end wrench, stamped "Made in U.S.A." on the face, with "Zenel" in forged raised letters on the shank. The back side shank has a forged-in code "KW" (not shown).

The overall length is 9.5 inches, and the finish is chrome plating.

The "W" year code indicates production in 1945.

3733 Zenel 7/8x1 Open-End Wrench

Fig. 224. Bonney 3733 Zenel 7/8x1 Open-End Wrench, 1947.

Fig. 224 shows a Bonney Zenel 3733 7/8x1 open-end wrench, stamped "U.S.A." on the face, with "Zenel" in forged raised letters on the shank. The shank also has a forged-in code "IX..." visible at the left.

The overall length is 10.9 inches, and the finish is chrome plating.

This wrench shows a minor inconsistency between its forged-in date code and the stamped "U.S.A." marking on the face. The "IX" code would normally indicate production late in 1946, but the "U.S.A." marking indicates production in early 1947 or later. Since the stamped marking is added during actual wrench production, the wrench was likely produced in 1947.

3033C Zenel 15/16x1 Open-End Wrench

Fig. 225. Bonney 3033C Zenel 15/16x1 Open-End Wrench, 1945.

Fig. 225 shows a Bonney 3033C 15/16x1 open-end wrench, stamped "Made in U.S.A." on the face, with "Zenel" forged into the shank. The shank has a forged-in code "KWx" visible at the left.

The overall length is 11.0 inches, and the finish is chrome plating with polished faces.

The "W" year code indicates production in 1945.

The equivalent model in the Bonney CV line can be seen as the Bonney CV 1033C Wrench.

3737 Zenel 1-1/16x1-1/4 Open-End Wrench

Fig. 226. Bonney 3037 Zenel 1-1/16x1-1/4 Open-End Wrench, 1947.

Fig. 226 shows an example of one of the larger Zenel models, a Bonney 3037 1-1/16x1-1/4 open-end wrench, stamped "U.S.A." on the face with "Zenel" forged into the shank. The shank also has a forged-in code "DX.." visible at the left, and shown as a close-up in the inset.

The overall length is 12.4 inches, and the finish is chrome plating with polished faces.

This wrench shows a minor inconsistency between its forged-in date code and the stamped "U.S.A." marking on the face. The "DX" code would normally indicate production in 1946, but the "U.S.A." marking indicates production in early 1947 or later. Since the stamped marking is added during actual wrench production, the wrench was likely produced in 1947.

3737 Zenel 1-1/8x1-1/4 Open-End Wrench

Fig. 227. Bonney 3737 Zenel 1-1/8x1-1/4 Open-End Wrench, ca. 1933-1941.

Fig. 227 shows another of the larger Zenel models, a Bonney 3737 1-1/8x1-1/4 open-end wrench, stamped "Made in U.S.A." on the face with "Zenel" forged into the shank. The back side shank has a forged-in code, but the mark is too faint to be read.

The overall length is 12.6 inches, and the finish is chrome plating with polished faces.

The chrome finish and "Made in U.S.A." marking suggest production in the range 1933-1941.

Zenel Electrical (Ignition) Wrenches

By the late 1920s Bonney had begun offering several types of miniature wrenches intended for electrical and ignition work. These wrenches were initially offered in the CV line as the No. 18 Ignition Set, with wrench models E2 to E11 custom-designed for specific ignition systems. (There were some really odd-looking tools in this set!)

With the advent of Zenel steel in 1933, new electrical wrench models were offered in the Zenel line. The older No. 18 set remained in the CV line at least until 1936.

Fig. 228. January, 1933 Catalog Listing for Zenel Electrical Wrenches.

The scan in Fig. 228 shows a listing for Zenel electrical wrenches, printed as page 38 of a January, 1933 supplement to the No. 33 catalog. (Since the electrical wrenches take up most of the page, we scanned the full page and the date can be seen in the lower right corner.)

The new Zenel electrical wrenches in the Exx series were of the obstruction style, with different offsets and sizes on each end. The model numbers from E14 to E30 were arranged in pairs to get each size with each offset, for example E14 (13/64x15/64) and E16 (15/64x13/64) made a pair.

Two sets were available, a No. 16 set with nine wrenches, and a No. 17 set with the same wrenches plus a screwdriver and pliers.

The 1934 catalog expanded the Zenel line to include miniature open-end wrenches in five sizes (H10 to H18), and the 1936 catalog added Zenel miniature box-end wrenches in four sizes (E40 to E46).

E16 Zenel Ignition Wrench

Fig. 229. Bonney Zenel E16 13/64x15/64 Ignition Wrench, with Inset for Back Side, ca. 1933-1941.

Fig. 229 shows a Bonney E16 13/64x15/64 ignition wrench in the obstruction style. The shank is forged with depressed panels, stamped "Bonney" and "Made in U.S.A." on one side with "Zenel" and the fractional sizes on the back side.

The overall length is 2.9 inches, and the finish is chrome plating with polished faces.

No forged-in code was found on this wrench.

E30 Zenel Ignition Wrench

Fig. 230. Bonney Zenel E30 7/16x1/2 Ignition Wrench, with Inset for Back Side, ca. 1941-1942.

Fig. 230 shows a Bonney E30 7/16x1/2 ignition wrench in the obstruction style. The shank is forged with depressed panels, stamped "Bonney" and "Made in U.S.A." on one side with "Zenel" and the fractional sizes on the back side. The back side shank also has a forged-in code "CQ....." at the right.

The overall length is 4.4 inches. The finish is plain steel with no trace of prior plating, and in addition the faces show some remaining marks from machining.

The "Q" year code would normally indicate production in 1938; however, with five dots following the date code and a plain finish, somewhat later production in 1941-1942 seems more likely.

H10 Zenel Miniature Open-End Wrench

Fig. 231. Bonney Zenel H10 3/16x7/32 Miniature Open-End Wrench, with Inset for Back Side Detail, 1938.

Fig. 231 shows a Bonney H10 3/16x7/32 miniature open-end wrench for ignition applications, stamped "Bonney" and "Made in U.S.A." on the face. The shank is marked "Zenel" in forged raised letters, and the back side has a forged-in code "LP" visible at the right.

The overall length is 2.5 inches, and the finish is chrome plating with polished faces.

This example is unusual in having its "Zenel" decal still mostly intact.

The "P" year code indicates production in 1938.

Zenel Combination ("TuType") Wrenches

In May of 1933 a catalog supplement provided the first listing for Zenel "TuType" combination wrenches, which were Bonney's first wrenches in this style. The combination wrench was a novel concept in 1933, and the name "TuType" was obviously intended to emphasize the mix of open and box ends.

Fig. 232. May, 1933 Catalog Listing for Bonney Zenel "TuType" Wrenches.

The scan in Fig. 232 shows the earliest catalog listing for the Bonney Zenel "TuType" wrenches, printed as page 41 of a May, 1933 supplement for the 1933 catalog. (The preceding page 40 is dated May, 1933.)

This listing is historically significant, as it shows that Bonney offered combination wrenches at about the same time as the Plomb Combination Wrenches.

The Zenel combination wrenches were given model numbers in a 31xx series, with the last two digits specifying the size in 32nds. The catalog listing shows that four models were available, with sizes ranging from 3114 (7/16) to 3120 (5/8).

In addition, a No. 19 wrench set with all four sizes was available in either a cardboard box or a leatherette roll.

The "TuType" series was relatively short-lived — by 1939 the Zenel wrenches had been superseded by Bonaloy combination wrenches in the 11xx series, with a greatly expanded range of sizes.

The combination wrench was an important innovation for the tool industry, and Bonney was once again at the forefront of the change.

A Word About Date Codes

The date codes for our examples of Zenel "TuType" wrenches are evenly split between "CY" and "JY" codes, allowing us to make some interesting (if somewhat speculative) inferences about the early production of these tools. The "CY" code indicates a forging die made in March, just two months prior to the printed listing. It's reasonable to think that Bonney would begin production in March, in order to have some inventory available when the tools were announced in May. (And a March production date means that the "race" between Bonney and Plomb for combination wrench first-mover status was likely a dead heat.)

So if production started in March, the existence of a new die generation coded "JY" for October of 1933 could indicate that the first dies from March had worn out by then, suggesting that the new wrenches were selling very well. It's also possible that new dies were needed simply for increased production (i.e. more dies = more drop-hammers), again indicating that the tools were selling well.

If the new dies were replacing worn-out dies, that would give us a way of estimating the time value of the "dots" added to the date codes, which are thought to be a measure of the cumulative impressions struck by the die. In our limited examples the maximum dot count is four, suggesting a time value per dot of less than two months.

3114 Zenel 7/16 "TuType" Combination Wrench

Fig. 233. Bonney 3114 Zenel 7/16 Combination Wrench, with Inset for Back Side Detail, 1933.

Fig. 233 shows a Bonney 3114 7/16 combination wrench, stamped "Made in U.S.A." on the face (though almost illegible due to pitting), with "Zenel" in raised letters forged into the shank. The back side is marked with "3114" forged into the shank, with a forged-in code "CY..." visible at the right.

The overall length is 4.9 inches, The finish is chrome plating, but with extensive losses due to rust and pitting.

This tool was one of the examples that helped to calibrate and test the Bonney Date Code System. The limited production period for the "TuType" wrenches gave us an a priori estimate of 1933-1938 for the production date, and the "Y" year code fits the first year of that range.

The "CY..." date code for this example indicates that the forging die was made in March of 1933, and the three dots suggest somewhat later actual production.

3118 Zenel 9/16 "TuType" Combination Wrench

Fig. 234. Bonney 3118 Zenel 9/16 Combination Wrench, with Inset for Back Side Detail, 1933.

Fig. 234 shows a Bonney 3118 9/16 combination wrench, stamped "Made in U.S.A." on the face, with "Zenel" in raised letters forged into the shank. The back side is marked with "3118" forged into the shank, with a forged-in code "CY...." visible at the right.

The overall length is 5.8 inches, and the finish is chrome plating.

This tool was one of the examples that helped to calibrate and test the Bonney Date Code System. The limited production period for the "TuType" wrenches gave us an a priori estimate of 1933-1938 for the production date, and the "Y" year code fits the first year of that range.

The "CY...." date code for this example indicates that the forging die was made in March of 1933, and the four dots suggest somewhat later actual production.

3120 Zenel 5/8 "TuType" Combination Wrenches

Fig. 235. Bonney 3120 Zenel 5/8 Combination Wrench, with Inset for Back Side Detail, Late 1933.

Fig. 235 shows a Bonney 3120 5/8 combination wrench with a paneled shank, stamped "Made in U.S.A." on the face, with "Zenel" in raised letters forged into the shank. The back side is marked with "3120" forged into the shank, with a forged-in code "JY." visible at the right.

The overall length is 6.2 inches, and the finish is chrome plating with some loss due to wear.

This tool (Fig. 235) was one of the examples that helped to calibrate and test the Bonney Date Code System. The limited production period for the "TuType" wrenches gave us an a priori estimate of 1933-1938 for the production date, and the "Y" year code fits the first year of that range.

The "JY." date code for this example indicates that the forging die was made in October of 1933, and the single dot suggests production soon after that.

Fig. 236. Bonney 3120 Zenel 5/8 Combination Wrench, with Inset for Back Side Detail, ca. Late 1933-1934.

Fig. 236 shows a similar Bonney 3120 combination wrench, stamped "Made in U.S.A." on the face, with "Zenel" in raised letters forged into the shank. The back side is marked with "3120" forged into the shank, with a forged-in code "JY..." (not shown).

The overall length is 6.2 inches, and the finish is chrome plating with some loss due to wear.

This tool (Fig. 236) was one of the examples that helped to calibrate and test the Bonney Date Code System. The limited production period for the "TuType" wrenches gave us an a priori estimate of 1933-1938 for the production date, and the "Y" year code fits the first year of that range.

The "JY..." date code for this example indicates that the forging die was made in October of 1933, and the three dots suggest somewhat later production in late 1933 or 1934.

Zenel Box-End Wrenches

Z2804 Zenel 3/8x7/16 Short Offset Box-End Wrench

Fig. 237. Bonney Z2804 Zenel 3/8x7/16 Short Offset Box Wrench, with Insets for Side View and Back Side Detail.

Fig. 237 shows a Bonney Z2804 3/8x7/16 short offset box wrench, stamped "Made in U.S.A." on the side of the shank. The shank is marked with "Bonney" and the model number forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "CW..." at the left. (The leading "Z" of the model number is hard to read, but can be seen in the enlarged photograph.)

The overall length is 5.2 inches, and the finish is chrome plating.

2807 Zenel 5/8x3/4 Offset Box-End Wrench

Fig. 238. Bonney 2807 Zenel 5/8x3/4 Offset Box-End Wrench, with Insets for Back Side and Side.

Fig. 238 shows a Bonney 2807 5/8x3/4 offset box wrench, marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. A forged-in code "DY." is visible on the back side shank at the left.

The overall length is 8.8 inches, and the finish is chrome plating with losses due to wear.

Z2808 Zenel 3/4x7/8 Offset Box-End Wrench

Fig. 239. Bonney Z2808 Zenel 3/4x7/8 Offset Box-End Wrench, with Insets for Side View and Back Side Detail.

Fig. 239 shows a Bonney Z2808 3/4x7/8 offset box wrench, with "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The shank also has a forged-in code "CV....." visible at the right.

The overall length is 10.3 inches. The original finish was chrome plating, but much of the finish has been lost due to wear.

One detail to note here is that the "2808" of the model number is forged into the shank, but that the leading "Z" is stamped. This indicates that model number change went into effect after the forging die had been finished.

The corresponding wrench in the later Bonaloy brand can be seen as the Bonney Bonaloy 2808 Wrench.

Z2814 Zenel 7/16x7/16 Single-Offset Box-End Wrench

Bonney was one of the select few companies to produce single-offset wrenches, a configuration with two box openings of the same size, with one offset and the other straight. This style of wrench was very popular in the later 1920s and early 1930s, but gradually fell out of favor with the rise of the combination wrench.

Fig. 240. Bonney Z2814 Zenel 7/16x7/16 Single-Offset Box-End Wrench, with Insets for Side View and Back Side Detail.

Fig. 240 shows a Bonney Zenel Z2814 7/16x7/16 single-offset box-end wrench, marked "Made in U.S.A." in forged raised letters, with "Zenel" on the back side. The back side shank has a forged-in code, but it's too faint to be read.

The overall length is 8.2 inches. The original finish was chrome plating, but only a few traces remain now.

Z2816 Zenel 1/2x1/2 Single-Offset Box-End Wrenches

The next several figures show examples of the Bonney Z2816 model.

Fig. 241. Bonney Z2816 Zenel 1/2x1/2 Single-Offset Box-End Wrench, with Insets for Side View and Back Side Detail, 1940.

Fig. 241 shows an earlier Bonney Zenel Z2816 1/2x1/2 single-offset box-end wrench, with markings "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "HR" visible at the right.

The overall length is 8.9 inches, and the finish is chrome plating with polished ends.

Based on the recently decoded Bonney date code system, the "R" year code on this example corresponds to production in 1940.

Fig. 242. Bonney [Z]2816 Zenel 1/2x1/2 Single-Offset Box-End Wrench, with Insets for Side View and Back Side Detail, 1945.

Fig. 242 shows a later Bonney [Z]2816 1/2x1/2 single-offset box wrench, marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, with "Zenel" forged into the back side. The back side shank also has a forged-in code "AW.." visible at the right.

The overall length is 8.9 inches, and the finish is chrome plating with polished ends.

The "W" year code indicates production in 1945.

Note that although the expected model number for this wrench would be "Z2816", the "Z" prefix has been omitted on this example. The 1945 production date offers a possible explanation for this anomaly. According to the catalog descriptions, by 1947 (or earlier) the Zenel single-offset wrenches had been superseded by Bonaloy models, with the model numbers dropping the "Z" prefix. Since the Bonaloy single-offset models shared the same design and specifications, the forging dies for Bonaloy and Zenel versions would have been the same except for the markings. If Bonney was gearing up for the switch to Bonaloy, the Zenel production might have shared half of the die, with the "Z" prefix intended to be stamped but omitted from this example.

Fig. 243. Bonney Z2816 Zenel 1/2x1/2 Single-Offset Box Wrench, with Insets for Side View and Back Side Detail, 1945.

Fig. 243 shows another later Bonney Z-2816 1/2x1/2 single-offset box wrench, marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, with "Zenel" and a forged-in code "AWv.." on the back side. (The forged-in code is shown in greater detail in the middle inset.)

The overall length is 8.9 inches. The finish is chrome plating, with some losses due to rust.

The "W" year code indicates production in 1945.

Fig. 244. Bonney Z2816 (NAF39460-2) Zenel 1/2x1/2 Single-Offset Box Wrench, with Insets for Side View and Back Side Detail, 1945.

Fig. 244 shows a very similar Bonney Z-2816 single-offset box wrench, dual-marked with the NAF model "NAF39460-2" stamped on the side of the shank. The shank is marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, with "Zenel" and a forged-in code "AWv..." on the back side. (The forged-in code is shown in greater detail in the middle inset.)

The overall length is 8.9 inches. The finish is plain steel, with extensive pitting due to rust.

The "W" year code on this wrench indicates production in 1945, and the NAF model number indicates production for a military contract.

Z2818 Zenel 9/16x9/16 Single-Offset Box-End Wrenches

Fig. 245. Bonney Z2818 Zenel 9/16x9/16 Single-Offset Box-End Wrench, with Insets for Side View and Back Side Detail, 1937.

Fig. 245 shows a Bonney "Zenel" Z2818 9/16x9/16 single-offset box-end wrench, marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "JO...." visible at the right (see lower inset).

The overall length is 9.6 inches, and the finish is chrome plating.

The year code "O" on this example indicates production in 1937, in the second cycle of the Bonney date code system.

Fig. 246. Bonney Z2818 Zenel 9/16x9/16 Single-Offset Box-End Wrench, with Inset for Back Side Detail, 1937.

Fig. 246 shows another Bonney Z2818 single-offset box wrench, marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "JO..v" (not shown).

The overall length is 9.6 inches. The finish is chrome plating, but now worn through in many areas.

An example of the earlier CV version of this model can be seen as Bonney CV 2818 Single-Offset Wrench.

Z2820 Zenel 5/8x5/8 Single-Offset Box-End Wrench

Fig. 247. Bonney Z2820 Zenel 5/8x5/8 Single-Offset Box-End Wrench, with Insets for Side View and Back Side Detail, 1937.

Fig. 247 shows a Bonney "Zenel" Z2820 5/8x5/8 single-offset box wrench, with markings "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "BO.v" visible at the left.

The overall length is 10.3 inches, and the finish is chrome plating with polished ends.

The year code "O" on this example indicates production in 1937, in the second cycle of the Bonney date code system.

An example of the earlier CV version of this model can be seen as Bonney CV 2820 Single-Offset Wrench.

Z2822 Zenel 11/16x11/16 Single-Offset Box-End Wrench

Fig. 248. Bonney Z2822 Zenel 11/16x11/16 Single-Offset Box-End Wrench, with Inset for Back Side Detail.

Fig. 248 shows a Bonney "Zenel" Z2822 11/16x11/16 single-offset box wrench, with markings "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "FY.v..." visible at the right.

The overall length is 10.9 inches, and the finish is chrome plating with polished ends.

The model number on this example is forged in as "Z-2822", in contrast to a previous figure with a stamped "Z" prefix.

Z2826 Zenel 13/16x13/16 Single-Offset Box-End Wrench

Fig. 249. Bonney Z2826 Zenel 13/16x13/16 Single-Offset Box Wrench, with Insets for Side View and Back Side Detail, 1945.

Fig. 249 shows a Bonney "Zenel" Z2826 13/16x13/16 single-offset box wrench, with markings "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "AW.v" visible at the right, and shown as a close-up in the middle inset.

The overall length is 12.5 inches, and the finish is chrome plating with polished ends.

The "W" year code indicates production in 1945.

Z2830 Zenel 15/16x15/16 Single-Offset Box-End Wrench

Fig. 250. Bonney Z2830 Zenel 15/16x15/16 Single-Offset Box Wrench, with Insets for Side View and Back Side Detail, ca. 1942.

Fig. 250 shows a Bonney "Zenel" Z2830 15/16x15/16 single-offset box wrench, marked with "Bonney" and "Made in U.S.A." forged into the depressed panel, and with "Zenel" forged into the back side. The back side shank also has a forged-in code "JO...v..." visible at the left, and shown as a close-up in the middle inset.

The overall length is 13.7 inches, and the finish is plain steel.

Estimating the manufacturing date for this example may require a bit of judgement. The "O" year code and "Zenel" marking would normally indicate production in 1937; however, the plain steel finish (with no trace of prior plating) suggests wartime production. Since the forged-in code is followed by an unusually large number of dots and a "V", this supports a later manufacturing date, possibly in 1942.

An example of the earlier CV version of this model can be seen as Bonney CV 2830 Single-Offset Wrench.

2894 Zenel 7/8x15/16 Box-End Wrench

Our next figure shows an example of a Zenel angled box wrench, and with a stamped (rather than forged-in) Zenel marking.

Fig. 251. Bonney 2894 Zenel 7/8x15/16 Box-End Wrench, with Insets for Side View and Back Side Detail, ca. 1936.

Fig. 251 shows a Bonney 2894 7/8x15/16 box wrench with an oval shank, stamped "Bonney" and "Made in U.S.A." on the front with a "Zenel" marking stamped on the back side. A forged-in code "JZ" can be seen on the shank at the right, near the box end.

The overall length is 12.4 inches, and the finish is chrome plating with polished ends.

Currently our only reference for this wrench model in Zenel steel is the 1936 Bonney catalog. (We don't have a 1935 catalog, so it's possible that the wrench appears there as well.) This wrench style was only briefly available in Zenel, as by 1938 the 289x series was listed as part of the CV line, and by 1939 as using Bonaloy steel.