5513 Caseback thread size?

[RickFlorida]

Hello everyone,

 

The short question is what is the thread size/name for the actual caseback on 5513's (and I assume 1680 and Tudor 7928 is the same)?   I see that people like Automatico have posted the size is 30.9mm but what is the pitch?  The threading of the midcase for the crown tube is 3.0mm x .35  correct?  The ".35" at the end of 3.0mm X .35 for the crown tube is the pitch.  We need to know the pitch of the 30.9mm caseback threading in order to reproduce the case.  

 

In my quest to explore how 5513 cases might be made which must have an expired patent on........I am still brainstorming on this.   I have given up on 3D printing as an option as it really would not work.  If we tried 3d Printing a case, you would still need to machine it to finish the threading and apply a correct finish to the surface.  This would just make it cost more than designing a CAD file and having it CNC'd because by 3d Printing, you essentially would be making the case twice.

 

My new option is to make a CAD file either by designing it from scratch or by using a potential contact to reverse engineer a case I have.  I don't know how far I can get but I will try.   I'm not totally against the fact that we have to pay 1200 bucks to Phong to get a complete case that we know is great and even would ship from and stay in the USA, but a CNC file would preserve our ability to get these.  I think people will stop making these and I hate that when I asked for a sterile version of a 5513 replica case, I had to pay more when I got it from Vietnam.   

 

Thank you!

Edited April 7, 2020 by RickFlorida

[RickFlorida]

I found this information today.   Any thoughts?

  https://forums.watchuseek.com/f6/thread-sizing-watch-backs-1289674.html

 

Particularly this statement:      "metric threads are typically sized such that the tapping size is thread designation minus the pitch. m39x0.5 would have a minor dia of 38.5mm, 60 degree thread form, 0.5mm pitch

if i was making a case and back that's about where I'd start."
Dave

[RickFlorida]

And here the old threads are repaired on a 5513, they just make a cutting tool at 60 degrees after laser welding enough material back on the old threads.  But I'm curious what the actual thread size is like if you made a tap and die.

http://www.laboratorioportanova.eu/index.php/portfolio/lavori-su-casse/restauro-di-una-cassa-rolex-submariner-ref.5513/?lang=en

[RickFlorida]

This question has been solved.  Davide Biguzzi of http://www.laboratorioportanova.eu/index.php/contatti/  kindly shared with me the following answer.

 

The Rolex 5513 (and I assume the 1680 and Tudor 7928) had the following thread size for the midcase.   (This should be the "tap" size if you had one made to create a case from scratch on a lathe)

diameter 31.00 mm and 0.5 pitch,It is a metric size with 60 degree thread profile

So we have known the tap size for the crown tube for years, 3mm X .35     and now we finally know the tap size for the where the case back screws on.