Handwheels on a retrofit? Why!? was Re: software questions DRO

--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
wrote:

> The most important reason to not use a CNC machine manually is a

safety issue. A mill with ballscrews is unlike a mill with acme
threads in that: when force is applied to the table it will "feed"
the ballscrew. Acme threads have an inherent binding effect.

Ron
This isn't usually true, more like a wives tale. If your ballscrew
pitch is much more than .5 turn/inch it won't backdrive. Most mills
are several turns per inch. If this wasn't true Bridgeport would not
have offerred a manual mill with ballscrews. Check out the ballscrew
company web sites.

Roger S.