Re: Newbie question on Ballscrews....

Thanks Jon....
Looks like I need to do more research :(..

Dave.

--- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> dspinnett@y... wrote:
>
> > Hi all.
> >
> > I recently bought a new 2hp Grizzly mill/drill, and would like to
> > convert to ball screws in preparation to a CNC conversion
> >
> > 1. Could you recommend a particular style, brand and where to
get?
>
> Note that many lower-cost ballscrews are not anti-backlash, and
> are made for power transmission, not precise positioning.
>
> > 2. What kind of quality do I need to keep .001 or better in a 6"
or
> > so work envelope?
>
> Well, you need anti-backlash nuts, and probably a low-precision
> ground screw. You could use selected rolled screws, but you
> can't guarantee .001" error over 6" with pedestrian rolled screws.
> Over that distance the variation in pitch would be small, though,
> so you could compensate in the software by selecting the right
> number of steps/inch.
>
> > 3. If I buy a ballscrew, what to I do with the ends where it goes
> > into the blocks on the mill? Are the ends turned, or do I need to
> > modify the ends somehow?
>
> You will probably need to turn the ends down to fit whatever end
> bearings you use. Generally, you would use two bearings,
preferably
> angular contact types, at one end, with a spacer or preloading
> 'thimble' that squeezes the bearings together to eliminate any
> axial free play in the leadscrew. For a 6" travel, you can
probably
> skip the far end bearing completely. Note that these screws are
> hardened, so carbide tooling is almost the only way to turn them.
>
> Jon