On Thu, 31 Jul 2008 21:44:22 GMT, (DaveB) wrote:

On Thu, 31 Jul 2008 12:56:31 -0700 (PDT), "Denis G."
wrote:

Sometime recently I read about someone who acquired an older milling
machine that had hydraulic feed on the table. I wondered about how
these tables might be controlled and if any lathes have been designed
using hydraulics to move the carriage or crossfeed instead of lead or
feedscrews. (After all, there are mechanical, hydraulic and pneumatic
linear actuators.)
I don't know if you could control hydraulics as precisely as
feedscrews (with respect to headstock spindle rotation) for cutting
threads, but you'd never have to worry about worn screws and metric/
inch conversions. I imagine that the big problem is in designing the
feedback system and getting it to respond well.
I've seen descriptions of hydraulic systems made by companies like
Enerpac that control the balancing of bridge sections to keep them
level while being positioned with cranes. I know that hydraulics can
be controlled with electronics and proportional or servo valves.
Probably it's difficult to beat mechanical feed and leadscrews because
it's a simple and accurate system, but I was just curious.


This is something we do all the time and is very common on spinning
machines because of the high forces required.

We can hold tolerances as well as if not better than a leadscrew
because of no mechanical influences.

http://s32.photobucket.com/albums/d1...nt=Spinvid.flv


Interesting industrial video, but wow!! the next pic is a keeper :-)
Care to share the details??? ED





Our website is www.debcomachinery.com.

If you need any further info let me know


Daveb