Re: [CAD_CAM_EDM_DRO] Another silly newbie question

The Sheppard Residence wrote:

> I appreciate the use of a ball screw to reduce backlash, do I assume this
> totally replaces any existing thread (acme etc.) present on the
> table/quill?

Yes, in general. It is possible, and I've heard of it being done, to build a
new nut which is designed such that balls ride on the edge of the Acme
screw threads. It sounds like a very bad idea, in terms of wear and
resistance to denting of the screw.

So, generally, the screw and nut are made as a matched set, and you replace
the Acme screw and nut with the ballscrew and nut. Retrofit kits are
designed so the ballscrew assembly bolts right on where the Acme
parts went.

Now, on the quill, most mills, mill/drills, etc. use a rack and pinion
mechanism to feed the quill. This has WAY more backlash than
most Acme screws. So, here, if you want low backlash, you have
to make a completely different mechanism, to bypass the rack and
pinion.

Jon