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Plomb: A Gallery of Tools


[Logo from Plomb 4011 Gear Puller]
PLVMB Logo on Plomb 4011 Gear Puller Yoke, ca. 1945-1948.

Table of Contents

Introduction

The Plomb Tool Company was an important and innovative maker of automotive hand tools during the first half of the 20th century, growing from a modest blacksmith shop to become one of the largest producers of hand tools. Then through an odd problem with trademarks, Plomb lost the use of its main brand name in 1950, leaving a legacy of Plomb-marked tools as a snapshot of early to mid-20th century tool production.

This page will look briefly at the company's history, and then show some examples of the many tools produced by Plomb.

Company History

The Plomb Tools Page (PTP) mentioned in the References section has an excellent discussion of the history of Plomb Tools; therefore, we'll present only a very brief summary here.

The Plomb Tool Company had its beginning in 1907 as a small blacksmith shop in Los Angeles, taking its name from one of the principals, Alphonse Plomb. The company expanded into the automotive tools market during the 1920s, and its first catalogs were published in the mid 1920s.

As early as 1930 Plomb had established a branch office in Chicago, located at 627 W. Washington Blvd., and the company was listed in the 1930 Donnelley's Industrial Directory. Plomb continued to grow rapidly during the 1930s.

In 1941 Plomb expanded its operations with the acquisition of the P & C Hand Forged Tool Company of Milwaukie, Oregon. (See our article on P&C for more information.) This was quickly followed by the 1942 acquisition of the Penens Corporation, which later became well known for its Fleet and Challenger brands of tools. Around this same time Plomb landed a major tool supply contract with the U.S. Government, for which it shipped a special line of "Wright Field" WF series tools.

The expansion continued in the postwar era with the 1947 acquisition of the J.P. Danielson Company, a maker of pliers and adjustable wrenches. (See our article on the J.P. Danielson Company for more information.)

In 1946 Plomb ran into an odd problem: it was sued for trademark infringement by Fayette R. Plumb, Inc., a company making hammers and other striking tools. According to an article in the Dec. 6, 1948 issue of Time magazine, the roots of the dispute went back to 1926, when Plumb objected to an attempt to register Plomb as a trademark. Apparently the companies negotiated an agreement at the earlier time, but later actions by Plomb were deemed to violate the terms.

As a result of this trademark dispute, Plomb was required to change the brand name marked on their tools, and chose "PROTO" (from "PROfessional TOols") as the new name. In 1948 Plomb started marking tools with the "PROTO" mark (this time making sure to register the trademark), and by 1950 the Plomb name had disappeared from its tools.

Although this forced name change may have been a nuisance at the time, the company itself was largely unaffected. Plomb continued operating as the Plomb Tool Company for a number of years after 1950, making the same tool models to the same specifications as it had before, but now marked "Proto Los Angeles".

Later History

In the late 1950s Plomb Tool changed its name to Pendleton Tool Industries and became a publicly-traded company in the stock market. A few years later the company was acquired by Ingersoll-Rand (IR), an industrial conglomerate, and afterwards operated as the Proto Tools division of IR. Eventually Proto Tools was purchased by The Stanley Works, and the successor to Plomb Tools operates today as the Proto Industrial Tools Division of Stanley.

Manufacturing Dates for Tools

Plomb is one of the few companies with a generally recognized date code system for its tools. The date code, when present, consists of a 0-9 digit giving the manufacturing year, with other markings providing the relevant decade. The PTP has an in-depth description of the date codes, so interested readers are directed there for further reading.

The main shortcoming of the date code system was that Plomb applied it to only a fraction of the tool production; many tools were simply not coded with a date. However, it turns out that other markings on Plomb tools were changed fairly frequently, so that by examining these markings (and possibly other characteristics of the tool), an approximate date of manufacture can be determined in most cases.

In order to provide a framework for examining the various tool markings, we first need to divide the production years into distinct periods.

The Early Period, Up to 1933.

This period covers a relatively long interval of time, but as tool examples and catalog resources from this era are both scarce, it may be difficult to estimate dates for the earliest tools. Plomb's date code system was commenced in 1927 during this period, but prior to that, tool markings may provide a clue to the manufacturing date.

The most notable marking is the use of the name "Plomb Tool Mfg. Co." on early tools, sometimes shortened to "Plomb T.M. Co." or just "Plomb TMCO". These markings are shown in a 1924 Ducommun industrial catalog on a variety of Plomb tools. The presence of the "Plomb Tool Mfg. Co." marking (or equivalent) probably indicates manufacture in or before 1927. An example of an early "Plomb TMCO" markings can be seen on the Early Plomb TMCO Wrench; note that the Plomb name has arrowhead-like symbols on either side of the name, even on this very early example.

For Plomb tools produced from 1927 through the end of this period, the expected marking would be the Plomb name with a conventional (round) "O" as "PLOMB". The tools may also be marked with "Los Angeles", but the key to this period is the round "O". The date code (if present) will be one of the digits {7,8,9,0,1,2,3} combined with a letter, signifying the years 1927-1933.

[Plomb DD16 1/2-Drive 1 Inch Socket]
Fig. 1. Plomb DD16 1/2-Drive 1 Inch 12-Point Socket with Date Code "8B", 1928.

Fig. 1 shows an early Plomb DD16 1/2-drive 12-point socket with the typical marking for this period.


The Los Angeles Period, 1934-1938

In 1934 Plomb started using a stylized inverted triangle for the "O" in "PLOMB", so that it looks more like "PLVMB" at first glance. The tools were still marked with "Los Angeles", so we'll use that as the name for this period. Date codes in this period will include one of the digits {4,5,6,7,8}, and sometimes "9". (Date code changeovers didn't necessarily occur at a year boundary, and sometimes took a few months to complete.)

[Plomb 5348 1/2-Drive Deep Socket]
Fig. 2. Closeup of Plomb 5348 1/2-Drive 7/8 Deep Socket with Date Code "5A", 1935.

Fig. 2 at the left shows a closeup of a model 5348 socket with the new Plomb "PLVMB" logo and "Los Angeles" marking. The "5A" date code indicates production in 1935.

Fig. 3 shows a model 2010 3/16 x 1/4 brake wrench, with date code "8B" indicating 1938 production. The finish of the wrench is polished steel with no plating.

[Plomb 2010 Brake Wrench]
Fig. 3. Plomb 2010 3/16x1/4 Brake Wrench, with Inset for Date Code "8B", 1938.

The USA Period, 1939-1945

In 1939 Plomb dropped the "Los Angeles" marking in favor of "Made in U.S.A." on its tools, so we'll call this the USA Period. Plomb continued to use the inverted triangle "PLVMB" logo for the company name.

Plomb discontinued its date code markings after 1942, so the codes for this period will include one of the digits {9,0,1,2} representing 1939-1942. Fig. 4 shows a model 3035 11/16x3/4 open-end wrench with a "1C" date code for 1941.

[Plomb 3035 Open-End Wrench]
Fig. 4. Plomb 3035 11/16x3/4 Open-End Wrench, with Inset for Date Code "1C", 1941.

This wrench has a thin chrome plating (worn off in areas), as by this time Plomb was starting to use plated finishes on its tools. (Many other manufacturers had done so since the early 1930s.) However, chrome finishes disappeared during the war years due to critical material shortages.

A significant change in socket production occurred in the USA Period with the adoption of a new hot-broaching process. Where the older process left an irregular shelf of material at the bottom of the broach, the new process instead formed a distinct annular cone from the displaced material. The differences can be seen easily by a comparison of old and new sockets.

[Plomb Sockets Showing Broaching]
Fig. 5. Plomb 54xx 1/2-Drive Sockets Showing Older and Newer Broaching Details (See text).

The change in socket production appears to have occurred around 1943, as dated examples from 1942 were made with the older process. Thus the socket construction can be used to distinguish earlier and later manufacture in the absence of a date code.

In Fig. 5 we have a series of model 54xx 1/2-drive sockets paired for comparison, with the older sockets (all date-coded) in the bottom row. The leftmost column (model 5425, 25/32) shows a 1941 socket vs. a post-1945 socket. In the middle column (model 5426, 13/16) we see a 1942 socket vs. a 1943-1945 socket. Finally, on the right (model 5430, 15/16) we have a 1939 socket vs. a 1943-1945 socket.

The USA Period also included the production of a separate line of Plomb tools, the WF series (for "Wright Field") produced for a large government contract. These tools are easy to identify by the "WF" prefix in their part numbers; the tools will have a "PLVMB" logo but not always a "Made in U.S.A." marking. The WF tools were produced from 1942 through 1945.

Another marking peculiar to the USA Period was the notation "War Finish" (not to be confused with "WF") to indicate that some aspect of the tool's material or workmanship had been compromised. Fig. 6 shows an example of a "War Finish" notation on a Plomb 8160 box-end wrench.

[Plomb 8160 Box-End Wrench]
Fig. 6. Plomb 8160 3/8 x 7/16 Box-End Offset Wrench, with Inset Showing "War Finish", ca. 1944-45.

If this notation indicated a shortage of materials (or labor), it might be thought to have been more prevalent during the last years of the war, and so suggests a manufacture date of 1944-1945. However, the example in Fig. 7 below appears to be from 1942, so some production problems may have occurred even earlier.

Fig. 7 shows another example of the "War Finish" marking, this time on a 1/2-drive model 5428 7/8 socket. The markings are "Made in U.S.A." with a "CC" code next to "War Finish", as shown in the inset.

[Plomb 5428 7/8 Socket]
Fig. 7. Plomb 1/2-Drive 5428 7/8 Socket, with Inset Showing "War Finish", ca. 1942.

The finish is plain steel.

The construction of this socket is cold-broached, which would suggest manufacture in or before 1942.

One other oddity in markings, apparently peculiar to the USA Period, has just been brought to my attention by a sharp-eyed reader. The PLVMB logo used by Plomb is generally flanked by arrowheads on either end, both pointing down to match the inverted "V". (Some would say these are really plumb bobs, added to irritate the Plumb tool company.) But on some tools made during the USA Period, one of the arrowheads may have been marked pointing up instead of down.

There are a number of examples of this sprinkled throughout this article; see for instance the 5285 Breaker, 4785 Breaker, WF-22 Breaker, WF-37 Breaker, or WF-83 Wrench. These particular cases have the righthand arrowhead pointing up, but other examples have been found with an Up/Down pattern. (No Up/Up examples so far though.)

Based on an unscientific sample, this marking oddity is uncommon but not actually rare, and appears to occur more frequently in the WF-series tools. The meaning of these markings, if any, is not known at this point; perhaps it was just a setup error on the marking machine.


The Pebble Period, 1945-1948

After the end of the war Plomb changed many of its tools to include a "pebbled" background on the flat forged areas. Tools continued to be marked with "Made in U.S.A." or the variant "MFD. U.S.A.", sometimes interchangeably on the same model. Fig. 8 shows a couple of typical examples of pebbled tools.

[Plomb 1218 Combination Wrenches]
Fig. 8. Examples of Plomb 1218 Pebbled Combination Wrenches with "Made in U.S.A." Variants.

Not all of the tool production was made in the new pebbled style; in particular, sockets were not amenable to this kind of forging.

In addition to the pebbled backgrounds, Plomb provided chromium plated finishes for most of its tools during this period.


The Proto Period, 1948-1949

On Jan. 23, 1948 (according to the trademark records, at least), Plomb began marking its tools with the new "PROTO" trademark, but also included a "PLOMB TOOL CO." mark. (Inverted triangles were used for all of the "O"s.) At the same time, the pebbled background was reduced to just a box surrounding the size markings, so these are sometimes referred to as the "pebbled size field" tools.

Fig. 9 shows two examples of double-open wrenches with this style of marking.

[Proto Plomb Tool Co. Wrenches]
Fig. 9. Wrenches Marked "Proto Plomb Tool Co." with Pebbled Size Fields, 1948-1949.

Unfortunately for Plomb, the inclusion of the "PLOMB TOOL CO." mark was considered a breach of the court agreement that settled their original trademark infringement lawsuit. Plomb ended up paying a considerable fine for this miscue, and in the final settlement was allowed to use the "Plomb" name on tools only through the end of 1949 (actually a few months into 1950). After this the Plomb name disappeared from the tools, but the company continued to operate as the Plomb Tool Co. for a number of years.


Summary of Production Periods

With an understanding of these production periods, you should be able to take most Plomb-marked tools and classify them into one of the periods. This will provide at least an approximate age for the tool, even when no date code is marked, and from there further refinements may be possible based on production details.

A few caveats apply, however. Plomb is known to have produced special-order tools for large customers, and these may not follow the standard marking rules. In addition, Plomb (like most major manufacturers) may have outsourced some of their production to smaller specialty companies, and these tools again may not follow the normal markings. For example, if the contract manufacturer didn't have the special marking die for the PLVMB logo, their production might have been marked with a round-O Plomb when the inverted triangle was expected.

That completes our brief introduction to the Plomb Tool Company. In the next section, we'll see some representative examples of their tools from the various manufacturing periods.


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