Re: Ball screws

> Between Christmas and New year I bought a Bridgeport series I with a 2j2
> head. (I think the machine was made in the early seventies).I am now busy
> with retrofitting it with EMC to a cnc system. What very important is for me
> is that I can use the mill in both the conventional way and the cnc way.
> Here is my question: When I replace the original lead screws for ball screws
> I will loose the self braking behaviour if it ( don't know this is the right
> word for it) which I need when machining parts by hand.
> Any comments?

If you use toothed belts to connect to your motors and as speed
reducers, these may provide a bit of replacement braking action as
they backdrive the unpowered motors. Steppers will cog a bit on each
step. With brushed servos I suppose you could put a small resistor
across the leads and get some electric braking action.

Not gotten that far yet myself,

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
30 Griswold Street, Cambridge, MA 02138
http://www.mdc.net/~stratton
(617) 492-3358 home/shop