Ball Screws for Mill

Crew:

The recent posts regarding steppers, lost steps and possible solutions has
shown me I'm really dumb. I hope I'm not the only one on the list who's only
catching a little of this thread. Very interesting but way over my head. :-)

But, I'm way too far into this mill conversion to back out now. I am trying to
retrofit a SuperMax YC-1 1/2 VA mill from Yeong Chin in Taiwan circa 1980.
It is a knee mill with 9x42 table. I suspect it is a direct copy of a
Bridgeport, it
at least looks like it.

I want to install ball screws in the X and Y axes and build a drive for Z
on the
spindle. I'm concerned right now with the X and Y conversion.

So, does anyone know if a Bridgeport X/Y retrofit kit is likely to fit this
mill? I
pulled the lead screws out and found them very close to the dimensions of the
retrofit kits I've found. I'd be grateful if anyone can confirm this
suspicion.

I plan to write manufacturers of these retrofit kits. They probably know
better
than anyone if this will work. I've found two manufacturers of these kits,
Thompson Saginaw and Power Trac. These both use precision rolled screws
which I want. I saw another with ground screws but didn't copy it, it's more
accurate than I need and was way out of my price range. I'd like to hear
of any
other manufacturers you know. McMaster Carr has one in its catalog but I
think it's a Thompson Saginaw (or they plagiarized the picture).

I'm planning to re-build the bearing brackets on the left side of the table
(X) and
on the front (Y) to hold these bearings and stepper motors. I'll then use
timing
belts from the motors to the lead screws. I'm pretty sure I can get a
retrofit kit to
work as I'm rebuilding these brackets. But it would be much easier if I could
copy the existing dimensions rather than design new brackets.

But, if this doesn't work, I'd like to hear of sources for ball screw stock
and ideas
on installing these. How are these machined, I assume they are hardened? Are
they hardened through? That would be a lot of stock to remove via grinding. I
will have to face these problem in designing and building the Z axis assembly
so any input would be helpful.

Any information regarding these companies willingness to work with hobby type
purchases would be helpful also.

Thank you very much. I think due to the expertise and help I can obtain
from this
list I may actually get something working. A very knowledgeable group.

TIA

Hugh
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Hugh & Denise Currin
currin@...
Klamath Falls, Oregon USA
541/884-3023
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