A Smooth Finish

Getting your Trinity Audio player ready...

In 1938 Chrysler Corporation introduced an improved method for finishing surfaces and eliminating scratches and other defects. Four years earlier, the company had conceived the idea in response to problems it was having with noisy wheel bearings. Chrysler developed the method in its mechanical laboratories and granted the Foster Machine Company in Elkhart, Indiana, a license to produce it. According to an article in the August 13 issue of The Truth, an Elkhart newspaper, it resulted in a finish that was quite a bit different than others. It described the smoothness of the resulting surfaces as “one-millionth of an inch, or even less,” and added:

“How much is a millionth of an inch? If a human hair were split into strands of one-millionth of an inch in diameter, you would have 9,000,000 strands of hair. And if a sheet of paper five-thousand[th]s of an inch thick should be cut into sheets of one-millionth of an inch in thickness, you would have 5,000 sheets.”

Superfinish Benefits

Chrysler started running full-page advertisements touting the new finish in magazines such as Popular Mechanics and Popular Science. In one of them, an automobile engine was depicted, with the caption “What?…An engine that will never wear out” above. This catchy title would certainly grab the attention of anyone with an interest in cars, and I imagine that would include a large percentage of the magazine’s readers. The qualifying text below stated “not quite that, of course….But a perfectly amazing increase in engine life through Chrysler’s new Superfinish!”

The remainder of the ad was devoted to an explanation of the process and the benefits of having it on engine parts. The last paragraph told readers:

“If you are interested in the story of Superfinish, write Chrysler Sales Corp, Detroit for a handsome, illustrated book and an attractive pocket piece; one side finished by fine grinding, the other Superfinished to the smoothness of glass.”

Advertising Medals

I’m aware of two types of the “pocket piece.” On one, the obverse inscription around the rim is DESOTO SUPERFINISH/FOR LONG LIFE, with a sample of the finish in the center. The reverse has a sample of a regular finish, with ORDINARY GROUND SURFACE around the rim. It is 38mm and struck in bronze. The other piece, also 38mm, is struck in nickel and has the same center, with SUPERFINISH/THE UNIVERSAL ULTIMATE FINISH DEVELOPED BY CHRYSLER on one side and GROUND SURFACE/1940 on the other. Both are common, indicating that large quantities were struck. I recently saw an advertisement for a variety of the 1940 Chrysler medal struck in bronze.

In May 1940 J.B. Wagstaff, general sales manager for the DeSoto branch of Chrysler Corporation, sent one of the medals, which was referred to as a “special coin” in an article published in the May 19, 1940, Cincinnati Enquirer, to every DeSoto salesman in the country. They were to carry them at work, and sometime during their sales presentations, “it will probably be jingled for a moment before coming out of the pocket to stress the point that DeSoto uses the Superfinish process on 13 important parts in 1940 models.” 

Free Samples

I assume the DeSoto medals were only sent to salesmen, and the Chrysler medals were mailed to those who wrote to request one. The “little steel discs” were sent in rectangular envelopes printed with information about Superfinish, suggesting that the recipient “test each side of the disc with your index fingernail. The tiny scratches you feel on one side are about ten-millionths of an inch deep—the satin smoothness of the other side results from—Superfinish.”

The envelope is no doubt many times scarcer than the medal inside it. I’m sure the company hoped the recipient would read it carefully before throwing it away. I haven’t examined The Story of Superfinish written by Arthur Swigert and published in 1940—as I mentioned, the company offered to send the hardcover book to anyone asking for one and, like the medals, they appear for sale regularly. 

Global Applications

By 1941 Superfinish was being used in aircraft engines manufactured for the U.S. government’s defense program, and also by the British government. The tank arsenal Chrysler built was among the many other uses found for the finish. Surprisingly, as early as 1940, newspaper advertisements of a number of large automobile dealers in Australia were promoting the company’s use of it in Chrysler, DeSoto, Dodge, and Plymouth engines, stating that it would add 15,000 miles to the car’s life.

I welcome readers’ comments. Write to me at P.O. Box 2866, La Plata, MD 20646. If a reply is desired, please enclose a self-addressed, stamped envelope. 

---

A version of this article appears in the October 2026 issue of The Numismatist (money.org)