I have sourced a period correct flat footed crown for my cal 321 Speedmaster but I’m worried that the tube size is wrong. I know the tube size is supposed to be 1mm but is that the inner or outer diameter of the tube? Here are the pics of the crown, it was stated it’s for a cal 321 Speedy but I’d like to get more eyes on it. Thanks in advance.

 

1mm refers to the inner tube size. What also distinguishes whether it is for Speedy or for SM300, RM is the thickness of the crown, which isn't shown here. I believe the thickness for Speedy's crown is around 3.8mm vs 3.3mm for the latter.

 

I just got the height measurement. See attached. It’s 3.4mm, which means it isn’t correct and I should stay away?

 

See the attached picture here from a member on the OF for the correct vintage Speedy crown (my apology for not remembering whose picture I took from). As you can notice, there is also an outer tube protruding above the edge of the crown.

 

I believe this crown’s tube pertrudes as well as you can see in the pic that displays the 1.2mm measurement. The side profile pic just has the tube on the other side of the caliper.

But this crown is 3.4mm thick. Which is concerning. It’s too far off the 3.8mm.

 

What is the asking price ?

 

It’s an auction.

 

Incorrect. For seamaster.

Correct one:

 

I think it is a SM 300 naiad crown.

 

eBay ?

 

Yes, and I won it. But I've asked the seller not to ship as I wanted to verify the dimensions. This was before I had a tube diameter as I was waiting on the seller to send it over.