Hi, folks.

I hope there’s a simple answer to this question, but Dr. Google has failed me.

A friend recently acquired a Hamilton military wristwatch from the 1970s. It has an aluminum case, and of course I’ve seen other vintage military watches with aluminum cases.

Not until today did I consider WHY the military might choose to order aluminum cases, vs stainless steel (of which I know there are many examples).

Dr. Google is very good on the differences between aluminum and stainless, but nowhere did I find anything that suggested an “aha!” moment.

Does anyone know why the military opted for aluminum?

(By the way, I came across dozens of sales listings for new aluminum watches, many pointing to a so-called “military look”.)

Thanks in advance, stay safe.

Can you post pictures of the front and back of the watch?

Thanks. Here’s the back:

Oops. Here’s the real back:

Sorry it’s tilted. Using a new photo program and still learning.

Thanks for the help on this question: why aluminum?

I'm not sure what alloy those cases are made of. And I'm not sure if the military contract specifications mentioned what the cases had to be made of, but it probably has something to do with avoiding corrosion and being antimagnetic.

That case looks like a parkerized steel case. Mil Spec cases for the GG-W-113 call for steel. BTW, the crown looks incorrect.

Thanks, I’m appreciating the knowledge (and re the crown). First time I heard of parkerizing. I will pass this along to my pal.

Again, thanks.

Are you sure it is aluminum? From the photo it looks like steel.

Thanks. I think we have concluded that it is parkerized steel.