"Bob La Londe" wrote in message
...
Ok, I've been playing with ,y Taig mini mill for a while now and I have
some idea of its limitations. I'm not quite ready to buy a lathe yet, but
I'm working on it. In the mean time I thought I might be able to make
some small parts if I could find a lathe style chuck to fit my mill.

It uses ER-16 collets so I was thinking, "just find a chuck with a 3/8
shaft, and use my 3/8 collet" There are a number of small inexpensive
chucks out there, but they all have a tapered shaft. At least all the
ones I can find.

For example
http://www.harborfreight.com/cpi/cta...temnumber=4486

If I had a lathe I could turn that shaft down to fit one of my collets,
but I'm not sure how to do that with my mill.

I do have an idea though. Clamp the chuck on a piece of 3/8 rod stock. Put
the rod stock in the collet. Turn the whole think to get a nice straight
shaft on the chuck. Reverse the assembly and drop out the rod stock. I
would need to buy a piece of rod stock that was machined to pretty good
tolerance, and I would have to accept the imperfections of the jaws since I
would not be able to turn them to be perfect before clamping the rod in
them, but it should be ok for some crude parts.

My big concern is whether or not my Z-axis stepper motor would flake out
with the extra weight. I have to keep my Z-Axis lead screw well lubricated
now to prevent lift fails in some ranges.

There will be cumulative error from this method, but I should be able to
turn stuff within 5 thousands (plus the any slop in the mill head) if I
start with a purchased piece of precision rod stock. Of course this sets
off a-whole-nuther chain of ideas. LOL.