On 22 Jun 2005 11:42:55 -0700, "phi117"
wrote:

What I think I need is something that I can use as a spacer between the
shoulder of the spindle and the chuck. I need to take up about a half
an inch of space between the shoulder and the chuck. The lathe uses 1 x
8 threads on the spindle so the outside diameter of the threads is
right at 1". Also, the two faces of the spacer need to be VERY
parallel in order to allow the face of the chuck to seat squarely and
run true.

Well, you've got a lathe, and I've heard of people turning aluminum on
a wood lathe in a pinch. (Though I would hope you've got some old
lathe chisels if you try that!) The only other thing that hasn't
already been suggested is using one of those nylon cutting boards.
You could turn it easily after roughing out a circle on the bandsaw,
and it'd be soft enough to drill with a forsner bit- though hard
enough for what you're doing, and waterproof to boot. They're pretty
close to parallel when when you get them, though they do have a little
bit of texture to them. I'd imagine you could smooth it off fairly
quickly with any number of methods, if you're concerned about it.
(FWIW, I wouldn't suggest a sander for smoothing plastic, though YMMV)

My second thought was to cut down a 1" PVC pipe coupling and use it as
a spacer, but I was unable to get good results from that. The coupling
was the perfect size, but I think the problem there was that I could
not get the ends sufficiently parallel on the cut, or the pressure from
tightening the chuck caused the PVC to warp a little. Either way, it
didn't work.

I think solid nylon stock would work a bit better for what you're
doing. The best would be machined steel, but the nylon would do in a
pinch.

My next idea is to make my own 1/2" MDF 'washer' to go between the
chuck and the spindle shoulder but I'm worried that the MDF may dent
and cause the chuck to run untrue. I'm going to try this out tonight
and see how it goes.

Skip the MDF, that's just going to be wasted effort.