Hello welcome to the forum.   I have added a couple of documents you may find worth reading TZIllustratedGlossary.pdf TM 9-1575.pdf

Funny I should come across this particular thread because I have a hairspring that I’ve just knocked the collet off!! It was too loose on the balance wheel and I was trying to tighten it (of course I failed!).  So I’m looking for a new balance myself. The hairspring is in quite good shape but obviously doesn’t have a collet now, so I don’t know if you’ll be able to use it. I wouldn’t dream of trying to refit the collet myself because I know exactly what would happen!! If I wanted to refit the collet to the hairspring (assuming I can find the original as it’s on the floor somewhere!!) where would I find a taper pin small enough? As some of you may know, this whole thing is tiny!!

Thank you. No value to me, and I guess not much value to anyone else either - just practice fodder as far as I see them. Ingersoll might make a nice watch to wear if I manage to service it. Benrus, I suspect, is too far gone in terms of case and dial - no cheap ways of getting them to decent looking condition? I wonder how these old movements compare to modern Chinese ones? Probably not favourably, even if there's nothing broken in them? Progress moves on? I've got an old Slava that I'm quite attached to, so I won't be learning on that one.

Welcome to the forum. You're best starting with something that you know runs well and keeps good time. That way when you've stripped and service it, any problems are due to something you've done.

Welcome to the WRT-Forum! Sorry to say it, but you’re very likely to break or lose something when servicing a wristwatch for the first time — I’ve been there! So, if these watches have any value to you, don’t attempt to service them as a beginner.