On Sep 27, 2:27*pm, Jamie M wrote:
Hi,

I bought a 4" 3jaw lathe chuck off ebay, and am adapting it as a 4th
axis for my milling machine. *The lathe chuck has a backplate with a
1.5" (1 1/2") spindle bore, and 1-1/2"-8 threads (8 threads per inch)

Is there an off the shelf pipe I could buy to thread into this and put
a couple bearings on the pipe to function as the lathe spindle? *I think
I might have to make this spindle on a lathe but it would be nice to
not have to!

cheers,
Jamie

It doesn't take long to do once you get set up. I made a dummy
spindle end for making chuck backplates, took an hour or so. That's
NOT a standard fastener or pipe thread. Or you could make a backplate
to fit whatever you're going to hook up the chuck to and fit it to the
chuck in place of the current backplate. Almost as much work as the
dummy spindle nose, I've done both. A three jaw wouldn't have been my
choice for such things, you can tweak a workpiece in a 4 jaw to be a
lot closer on center, but that's me.

Stan