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Sunday, November 5, 2023

1964 Mil-W-3818B DTU 2A/P (by Benrus)

You'll have to forgive this non-Hamilton post but I thought some folks might be interested.

Hamilton wasn't the only manufacturer to make military watches for the US (and other) military.  I'm definitely no expert on all-things military watch related but I do find the differences and similarities of various makers interesting.

One of the precursors to the  Mil-W-46374B and the GG-W-113 was the Mil-W-3818B made in the 1960s.  Military contracts were awarded then just like they are today - through competitive proposals that aligned with military specifications at the time.  Specifications defined the materials of construction, accuracy, luminescent requirements, durability, etc. and watch manufacturers would provide proposals to meet the requirements.  During WWII there were several awards for various wrist watches and in some cases different manufactures would even make parts for each other.

The Mil-W-3818B was made by Benrus and features their 17 jewel DR 2F2  caliber movement.  Unlike the Mil-W-46374B, the Mil-W-3818B was intended to be serviceable and is arguably more along the lines of the GG-W-113 in terms of quality.

I was recently sent a Mil-W-3818B for an overhaul, against my better judgement.  I really don't like working on non-Hamiltons, mainly because if something goes wrong I don't have access to spare parts like I do with most Hamilton calibers.  However, my arm was twisted and I was curious to see what would be the difference.

As received, it was in very-worn condition.  I removed the crystal and the crown before I decided to take photos for a blog post.  From this angle it looks like a Mil-W46374B

It took all of my strength to separate the two-piece stem.  In fact, I thought about just returning the watch unserviced - because I was afraid I'd break it.  But after checking photos of other examples online I decided to go for broke.

With the dial out of the way, this movement looks very ETA-like, and similar to many Hamilton movements.  It's a bit thicker, or more substantial though - but the design is very similar.

The back looks similar to a Hamilton too - like the 688 movement - but it has a three screw train bridge where Hamiltons only have two screws.  All of the screws on this movement are more substantial than a Hamilton caliber too.

With the balance cock removed you can see 2372 stamped.  There is no ETA symbol present but as I suspected, this movement is based on an ETA ebouche - just like Hamilton used at the time (and today as well).

The inside of the case back has no markings whatsoever.  I appear to be the first person to lay eyes on this movement in the past 60 years.

Disassembly, cleaning, and lubrication of this movement is just like every other ETA movement I've done.  I could probably do it in my sleep - but it still takes a bit of a delicate touch to get it all back together again.

The movement is ticking away with a good motion.  Without a crown, I haven't wound it fully but the watch timer will still give me an idea of performance.

Not too shabby... the amplitude is a little low but once it's fully wound it will come up to 230+.

The back of the case has all the markings one would look for in this model.  This watch dates to September 1964.  I added spring bars so a one-piece NATO strap will work.  Or a two-piece strap can be installed.

One of the specifications for this model is the second hand should have a luminous orange tip - so I relumed the second hand so it will glow again.  This actually turned out very nice but I think I'll still keep to Hamiltons, even though this is a very close cousin.

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