rethreading a pocket watch crown

[chaplin37]

good afternoon everyone, I bought a crown for a pocket watch that im working on which has a thread diameter of 1.55mm or a tap 2 as ive read everywhere that it is. I ordered it off of ofrei.com that said it had a 1.55mm. When i got it, the thread was too small and i tried my hardest to fit it on and it looks like i stripped the threading on the crown. I’m kinda nervous to order another one from them in fear that it is going to be to small and will have to waste more of the customers time by having to send the crown back to the company, because she really wants this pocket watch back. Has anyone ever ordered crowns and had this problem? Do you think maybe its just a one time thing and if i order another one it will actually be the correct thread size? and is there anything i can do to try to get the one that i stripped the thread on it to work with this watch? thanks everyone for the help

[chris mabbott]

Sometimes the stem and crowns are mismatched, so a stock part doesn’t fit, a common issue on antique watches Is this American or Euro watch?

I have this problem all the time as finding the exact match is difficult, I normally re-thread the stem and the crown to the same size when replacing a missing piece. You need a set of drill bits, taps and dies for this.

[chaplin37]

Thanks for the response, its an american pocket watch. Now another question for you, i found the tool to hold the crown in the lathe so that it can be rethread, now the arbor on this is 3.77mm and I cant find a 36 or 37 collet for my peerless lathe. My question is can i buy a jacob chuck to hold this tool in the head stock and also buy another jacob chuck for the tailstock to hold the tap?

[chris mabbott]

Fitting up work is a constant battle, there is always something that doesn’t fit…

You can use a Jacobs but the important thing is to true up the work with a dial indicator and obviously use great caution when tapping. I would turn it by hand and NOT by power.

If you have a collet holding tailstock, or some way to fit a jacobs into the TS, then yes. If you have some old crowns, do a practice run on one of those, to get the feel. Better to make a mistake on a test piece than the one you need.

[chaplin37]

Thanks, I just found a 36 collet, do you think i would be able to fit that 3.66mm tool into that?

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