Michael Koblic wrote:
I am slowly going through the milling machine. I have cleaned it, greased
it, trammed it all successfully. I have adjusted the gibs on all axes.There
is some backlash on the X and Y but nothing to worry too much about. The
run-out is 0.001" on the spindle and 0.002" on the chuck (but the rod I used
is of unknown concentricity so I am happy).

The one thing that drives me nuts is the Z-axis feed: For a start the
backlash is almost the whole revolution (.050" on a 0.060" wheel).
Furthermore, it is not very crisp or consistent (it is hard to tell when the
drive is actually engaged). I can see no way to improve on this and the
manuals are no help at all (the manual that came with the machine is brief
and Chinese - or might as well be!). I have downloaded two others related to
similar equipment including the notes from the Little Machine Shop (which is
the best) but none of them deal with this.

No surprise, the rack and pinion drive has to have
a lot of backlash. If you want fine control, you
need a screw drive of some sort. The rack and
pinion is only good for a drill press. You might
be able to rig a caliper to the Z axis to measure
the position. That will make your positioning
much more controllable, as at least you can READ
the position.

Should there not be a better way to pre-set the depth/Z-distance travel
without going through this palaver? Is this amount of backlash on the Z-axis
reasonable? Can it be corrected?
Does the machine have a depth stop? Most have
some sort of clamp-type gadget that can be
attached to stop at some particular depth.

Jon