Gene Martin wrote:

Roger Hull wrote in message us.net...
First, thanks to all who offered advice on my Clausing cross-slide leadscrew
repair problem.

I have ordered Acme threaded rod to make the repair, but I will need to
accurately bore out the center of it whichever repair method I settle on. The
two choices now (As I see it) it to either turn off the existing worn-out
threads (I have a second lathe, a 3.5 x 17 Sherline), and bore out the
threaded rod to fit over the original shaft, OR Bore out the threaded rod to
the minor diameter of the splines and duplicate the splines (Or have it done
for me).

Rodger,
I have a 5900 clausing with taper attachment. The spline is 0.410 and
the depth of the acme thread is 0.500, so there is not much room to
spare. My suggestion would be to turn the worn threads off so the
shaft is 0.498. I would get a piece of 3/4 12L10 leaded steel and
drill and ream it to 0.500. 7" is quite deep, so you will have to go
slow. I would silver solder the two pieces together and then turn the
OD to .625". Get a 10 pitch acme carbide insert (about $12).
Calculate the angles and make a holder for it. The 12L10 will thread
like butter. Carefully fit it to the bronze nut. I made a 5/16-14
lead screw for a small lathe I made. I bought the acme threading
insert, made theholder and had no trouble turning the thread.

If you are going to follow this route, use soft solder instead of siver
solder. It will require much less heat for less time to install, It will
be easier to remove later, when the free machining steel screw has worn,
and you will never break it loose from anything this side of a total
destruction type crash.

With soft solder, it will be quite within reason to be able to install
a sleeve without any scale forming. You could even make up a mandrell
and make a spare thread or two.

Cheers
Trevor Jones