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1940s Gruen Precision Very Thin Pan-American Pan-Am ACE watch, 420ss movement. The watch has been recently serviced.


For the full condition report, please scroll down.


It dates from 1946-1948 and was one of the more popular styles of the Pan American series. Prior to World War Two, Gruen had established a promotional relationship with several airlines, including Pan American. Once American involvement in the war began, Gruen found themselves in an odd position. Since they depended upon imported Swiss movements for their watches, they could not guarantee supply for what was considered a crucial strategic commodity, so they were not awarded any contracts for the production of US Government-issued military watches. Gruen President Benjamin Katz was a member of the War Planning Board.

Gruen were therefore still producing some watches for the civilian market, unlike the other American brands involved in military production. Gruen used their relationship with Pan American to capitalize on one of their material contributions to the war effort. The Pan American "Clipper" flying boats were among the few aircraft (early in the war) capable of making the long non-stop flights necessary to maintain contact with scattered outposts in the Pacific. Their cooperation with the US military in delivering supplies, messages and diplomats throughout the region was well-known, and the Clipper pilots gained a measure of celebrity. Beginning in 1943 Gruen began advertising that they were providing a new navigation watch to the pilots and crews of the Clipper flying boats, and that when the demands of the war relented, these watches would be made available to the public.

In August, 1945, with a broad media campaign, the civilian production Pan Americans were introduced. Most have the distinctive bold 13-24 hour inner dial, while some have very small 13-24 characters. Most have red sweep-seconds hands. The Pan American's are a fascinating piece of the Gruen puzzle, and offer a relatively attainable collectible watch with a good combination of history, style and functionality. 


Please see the images as these compliment and aid the description provided below.



To my eye the dial is an older, high quality restoration. Many of these dials struggled to stand the test of time and have been restored, most have been done quite poorly, of which this is not one.



The hands are original and maintain the thermally blued colour. Overall they aren't bent and are in good condition.



The crystal is in perfect condition with no scratches.



The crown appears to be a later replacement. In good condition.



The case is Stainless Steel and in very good condition with no dents or deep scratching, only light surface scratches.



The Stainless Steel case back is in very good condition. It has a couple of very light surface scratches.



A new 18mm genuine leather strap.



A Gruen 420ss movement, with 17 jewels and a power reserve of 40 hours. The movement has just been serviced. It is functioning perfectly.


Case dimensions

Case width: 32mm

Case width with crown: 33mm

Case length: 32mm

Lug to lug measurement: 39mm

Case depth: 9mm

Lug width: 18mm

1940s Gruen Precision Very Thin Pan-American Pan-Am ACE watch, 420ss, serviced

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