On Thu, 28 Jul 2005 09:13:06 -0700, Koz
wrote:

I have an old taiwan made 14 x 40 lathe (late 70's vintage, TWS brand)
which was already pretty beat when I aquired it (free!)

For the most part, things work well and it can maintain tolerable
accuracy for what I do so I would like to replace the one part that
brings it down: The cross feed screw. This screw is fairly typical in
style, several steps, each with different threads journals and keys for
the handles, bearings and such with a bronze nut on the under side of
the cross slide. Bronze nut is split with a wedge that adjusts via a set
screw to take up backlash. The wear in the middle is such that taking
up backlash there makes it tight at the ends of movement. Also, the
arrangement is constantly loosening.

So..here's the question. I know that I can't find an exact replacement
and need to scab together a new system. I can go high end and use a
ball screw, or lower end using something similar to what exists or
somewhere in between. My guess is that the designs haven't changed much
so I might be able to find a similar screw that could be modified from
the Grizzly or Jet parts depts.

Any suggestions on the best bet in the long run (other than buying some
better iron)? I hate to open a can of worms and turn this into a
nightmare project but it really needs to get done soon.

Thanks,

Koz
Ballscrews will turn if pushed on the end. So this means that if the
tool wants to dig in it can cause the ballscrew to turn which lets the
tool dig in even more. You may also have a hard time finding a
ballscrew with a pitch as fine as you current leadscrew. Acme thread
is best in this application.
ERS