a 3 jaw chuck is never to be used for something that will be taken out and re chucked. it is meant for roughing, or doing an entire part in one clamping. no 3jaw chuck (even "precision" 3 jaw chucks) is accurate enough to unclamp and re-clamp and be perfectly aligned, even a 4 jaw may not be good enough to re-chuck a part. only way to get a truly removable part and put it back accurately is to use a drive dog and turn between centers.
Which is a bit of an art form in it's own right, esp if the lubes goes fubar and eats the tip and the running seat of the center it runs upon. But there are ways and means of dealing with that too.
I learned a great deal about fine work, dealing with what I did as a hobby playing with a very small watchmakers lathe (in truth,a standard sized watchmakers lathe) a WW Pattern unit that I bought in the mid 1980's. Sharp tools were the order of the day, using hand held tools and cutting with a sewing machine motor driving the lathe with a leather bootlace.
Cutting a disposable mandrel from a piece of stock is another good way to make a part on a 3 jaw chuck that will allow you to repeat the removal and installation as well. The accuracy which with the mandrel is made, will dictate the accuracy of the repeat positioning. Doing this, you can remove and install such parts as bushings, where you may need to bore them out or shorten them.
There is much to be said for a shellac chuck, as far as removing and reinstalling work to run true is concerned. About as much to be said against it, too, from a practical point of view, but it is but one of many tools in the toolbox, as it were.
There is lots of good to be gained from reading about how it was done in the past, but one must keep in mind that to trap oneself there, for any reason but a historical recreation, is a bit foolish.
There is a lot of good literature out there, and of it, the hobby metalworking stuff likely has the most bearing upon a fella wanting to learn gunsmith machining, as it closely parallels the needs of a gunsmith, with more emphasis on making one good part, than several dozen or hundred per day. I recommend grabbing a few issues of Home Shop Machinist out of the States, and/or Model Engineers Workshop (a UK publication from the publishers of Model Engineer, with more emphasis upon workshop stuff than steam trains and engines).
If a fella can learn from books, there are a lot of good ones out there, and no fair few of crappy ones. Use the public library to borrow books to pre screen them. Buy the ones that suit your needs. Some, I would have been grossly disappointed in, had I purchased them, one called Machine Shop Secrets comes to mind. Borrow it from the library first.
Re-reading this post, it comes off a random collection of thoughts. If you get something useful from it, use that!
Cheers
Trev
