Keith,
Another option is to get a nice 3 jaw - metal lathe style chuck. These are the only chucks that I use, and they work very very well.
3-inch -- 3 jaw -- inside and outside jaws: Chuck
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www.amazon.com]
Back plate:
[
www.amazon.com]
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This style chuck typically comes with a plain back. That means that the back has 3 or more screw holes that are used to screw on the back plate of your choice that matches the particular lathe you are going to use
With any thread on chuck there may be minor variations in the threads. As a result, it may be necessary, if the backplate does not run 100% true -- i.e. with no wobble or run out - it may be necessary to remove the head stock shaft from your lathe. Then, take the shaft and the backplate to a machine shop where a metal working lathe can machine out any tiny runout or wobble that may be present on the match on your head stock shaft to your back plate. You will also want to send along the chuck so that the machine shop can do a final check of the chuck runout or wobble with the chuck mounted to the back plate while the head stock shaft is in the metal working lathe of the shop being machined.
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When I purchased my lathe and chucks, I also purchased semi machined back plates and simply sent the head stock shaft and the back plates to the machine shop for final machining before they were finally assembled. But in use the three chucks that I have and use have essentially 0 run out when being used due to the precise final machining of the backplate when it was on the head stock shaft.
Best wishes.
