Proper crown size for GMT (non ceramic)

[greg325i]

I'm looking to replace the crown/tube of a non-ceramic GMT. I think this would be a 16700 or 16750 vintage model. What size crown/tube do I need to look for?

On ebay, crowns are listed in mm sizes.

Also, does the stem of an ETA just fit into a new crown? How does that work? I'd like to be able to do this myself, but it might be above my pay grade.

 

[colt45gto]

twinlock or triplelock?

 

[greg325i]

Well, it has a triplock on there now, but I think the twinlock is correct on that watch. I'm looking for the proper twinlock in that case. I think the case set this watch was based on was for a sub, which would explain the improper crown on there currently.

 

[colt45gto]

http://www.cousinsuk.com/catalog/4/494/1955.aspx
a 6mm twinlock crown requires a c8360 case tube or pendant tube.

a daytona 7mm crown requires a c8363 tube.

 

[greg325i]

So what I'm looking for is a 6mm twinlock? Pardon my ignorance, but the 6mm refers to the diameter of the crown, right? If so, does that mean that all 6mm twinlock crowns are the same "height" ie. stick out the same distance from the case?

So I guess what I want to make sure of, is that the diameter is the same as the sub's triplock, but the crown is "shorter."

What about how the "stem" or whatever attaches to the crown?

Will most tubes fit into most cases?

Sorry for all the questions, but your information is most helpful!

 

[colt45gto]

http://forum.replica-watch.info/vb/...eplacing-rep-crown-68972?p=675592#post-675592

this might explain it better.

that is how you determine which case tube fits which crown.

 

[greg325i]

Dave,

Thanks a ton! Wish I had the proper tools for this. Looks like my WS will be tackling this mod.

Much appreciated.

 

[colt45gto]

oh btw, the original ETA winding stem will screw right in to the crown. the problem part is the fitting of the tube to the case and reeming the inside out to accept the crown.

 

[greg325i]

Off topic now, but speaking of ETAs, do you have a suggestion for sourcing a new set of GMT hands to fit an ETA? This GMT has the far-too-short GMT hand.

 

[colt45gto]

that isn't my forte you could try ofrie or search through some of the trusted dealers for parts? sorry i am of no use here.

 

[greg325i]

No worries! You've been a great help! Thank you.