11AOACD crown

Submitted by davep on

 

I need to source a crown for a 1973 Ambassador 11AOACD. I believe the measurements to be 4mm diam , tap 8 (1.1mm) 2mm tube, (In the Uk tap sizes seem to mean that a tap 8 = .8mm , tap 9 = .9 mm etc , all very confusing !)  As I cannot find anything here , before committing to buy even a generic crown from the US, at some expense for such a small item , would appreciate any advice whether my sizing is correct

Geoff Baker
Posted September 28, 2025 - 9:06pm

Watch case number? (stamped inside back) 

davep
Posted September 29, 2025 - 4:58am

Thank you both, Yes found that list but unsure why it  mentions both sizes . pretty certain it is 8 ,that is according to my callipers and dodgy measuring technique !  Case number is 7531-1 , typically , the spare parts list that I managed to find on the net listing cases starting with 7 jumped this number .

FifthAvenueRes…
Posted October 31, 2025 - 8:56am

In reply to by davep

The 11AOACD was used in several different cases, the case# / crown will determine if the correct stem is tap 8 or tap 10. 

I know for a fact the same is true for the 15J 10Ak and 16J 10AKCSH military issued watches.  Although interchangeable the 10Ak is tap 8 and the 10AKCSH is tap 10, both using different Crowns.  

Geoff Baker
Posted September 29, 2025 - 7:50am

Case 7531-1 with 11AOACD uses 385-3Y crown

davep
Posted September 29, 2025 - 7:53am

Sir, you are a star , many thanks 

davep
Posted September 30, 2025 - 7:16am

oops, I'll try and remember next time !