Some thoughts about Bell-Matic cases...

One of the pleasures of collecting vintage watches, particularly SEIKO Bell-Matics, is learning about how they were made (and what they were made of). Asking questions of the vintage SEIKO collectors' communities such as the SEIKO-Citizen Forum and the Poor Man's Watch Forum (PMWF) is a good way to educate yourself. To prepare this posting, I have benefited from the advice of several knowledgeable individuals, but, keep in mind, any errors or omissions are mine, not theirs. All that being said, let us talk about cases.

Bell-Matic cases appear to come in three "flavors:" stainless steel (which is usually highly polished) and two types of plated brass used for "yellow/gold" cases. As you can see from the two photos below (click on the image to see more pictures of that particular watch), plated brass can be identified as "SGP" or "base metal." I have been informed that when Bell-Matics were produced the technology to "gold plate" stainless steel did not yet exist. This would explain the use of brass cases for plating, as brass is a soft, malleable metal. I have also been informed by a COSERV representative that "SGP" means "Standard (or SEIKO) gold plate."

The designation "SGP" versus "base metal" may reflect manufacturing dates more than any significant difference in the plating process, but only a SEIKO archivist could answer that definitively. I have been told that the "SGP" designation appears on many SEIKO "yellow/gold" watches. (From my admittedly limited perspective, it is highly unlikely that any of these "yellow/gold" cases is solid gold, as that would result in a very high price.)

One assumption might be that during the production run of approximately ten years, the "SGP" designation was changed to "base metal." But this is contradicted by examples of watches whose caseback dates them to the earliest production days and those that date to the end of the production run. For example, the first photo above (4005-7000) dates to 1968 and it is identified as "SGP." The second photo (4006-6016) identified as "base metal" dates to 1971. However, two examples in the Bell-Matic Republic that date to 1974 and 1975 are identified as "SGP."

This would lead to the conclusion that the "SGP" and "base metal" designations do refer to a manufacturing process, rather than a production date.

You can also see that "yellow/gold" cases come in polished and brushed versions. Purchasing a "yellow/gold" Bell-matic can be risky, as these cases generally show wear very easily. The case was so badly worn that I decided to have its movement and dial swapped into a stainless steel case I found from a supplier (second photo)."Yellow/gold" cases can be replated but this can be fairly expensive.

I hope you have enjoyed this discussion and if you have comments or corrections, please feel free to add them to this post. Thank you for visiting!