Blancpain

I picked up a nice later 4K serial number milspec case that missing the moment and dial. When I stripped the case and studies the crown and tube I was surprised to see a different tube on the later 4K case. I have take a photo of the 4K milspec on the rig...  

Here is, for example, an untouched Milspec in the 5xxx series, with its small crown. ...  

So I can not check it this week. Please can you make a measure of the small crown. I guess there are different sizes on the run. NOS case? Grüße Stephan ...  

Are they fine for a big case? Thx Stephan ...  

I think, they are to small H11, M15 stands on your pg1 paper H for hour 11mm? M for minutes 15 mm?

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Is Like this, or is it for a small case Fifty Fathoms? ...  

The second one that I measure was 5.32mm x 3.20mm. I think if you could mount It on a big case it would be fine. I do have a extra O-ring for the small crown and if you need one PM your address and I'll send you one. Brian

This is a wellcome offer. Grüße Stephan

Unfortunately, many watchmakers have thought of improving the water resistance of these watches by replacing the old crown with a new "bi O'ring" with a new tube change. The old system is totally waterproof, I dived to -40 meters several times with my old...  

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Different types of the Fifty Fathoms PG 1 big case, baton hands, professionell type PGA big case curved hands, civilian type PF 1 small case Sorry for my bad Englisch

Saw these old brochures on IG... Seem to confirm the model references. instagram.com ...