On 11/27/2010 05:48 PM, Bob La Londe wrote:
I think I have a design for a Z-axis retrofit for it all worked out, and
I have a question or request for clarification from some of you guys who
have built, retrofit, or modified your own machines. Everybody says you
need a brake on the Z-axis if you use a ballscrew or it will backdrive.

I can't speak to the necessity of a brake, but how about
counter-weighting it so there is no force required for it to stay put.
It will increase the inertial load, but that is probably less of a
problem on the Z axis.

BobH