Best way to fit a stem

[highoeyazmuhudee]

I was wondering the best way to measure a stem for cutting to fit the movement and the case for length. brand new stem, ETA movement, and a TAIWAN Sub case. How do you calculate the length it should be to fit properly when pulled out to time setting pos and to the crown screwed down. any rules of thumb or methods to calculate this?

[Francisco]

I was wondering the best way to measure a stem for cutting to fit the movement and the case for length. brand new stem, ETA movement, and a TAIWAN Sub case. How do you calculate the length it should be to fit properly when pulled out to time setting pos and to the crown screwed down. any rules of thumb or methods to calculate this?

if you do not have a stem to cut at the same length... just be careful...cut a bit each time with very good pliers.

[RWG Technical]

It is a trial and error fit.

Install the new stem into the crown, insert in the case in the winding position, then note how much of the stem needs to be trimmed down, you want the crown to have about 2-3 mm of clearance from the crown tube. In other words, when you have the crown in the winding position, you should have to press down about 2-3 mm to engage the threads and screw it down.

ALWAYS trim longer than you expect, cut the stem with side cutters, then file the cut part so it's slightly rounded, any burr and you will ruin your crown threads. As you get closer to the required length, do NOT cut it anymore, use the file to reduce the length. It takes me 5-6 install's and removals to get a stem to the correct length, don't rush the job.

[highoeyazmuhudee]

thanks for ALL your info guys. I hate reinserting crown stems into movements, and wanted a more precise way to do it with out having to do it unnecessarily since im prone to dislodging the keyless works internals. and thats a REAL pain in the [censored] to reset especially once your watch is done and all that's left is putting that damn crown in for the last time. I find the keyless works to easy to screw up, but more so I wish there were a way to repair it from the bottom instead of having to go under the dial.

thanks The Zigmeister for the rounded stem tip, I always grinded it dead flat, and I suppose that's why my last crown fitting resulted in stripped crown threads.

Edited September 1, 2009 by highoeyazmuhudee

[FxrAndy]

Unfortunatly trial and re-trial untill it fits the way you want it.