Re: Bridgeport Ballscrew Backlash

Follow up:
I just measured the backlash at the ends of travel of
both the X and Y axis. To my great suprise, the backlash
of BOTH axis and BOTH ends of travel doubled??
Opposite of what you would expect. X at the ends of travel
is .010" and Y is .006". I confirmed that the center of
travel is half of these values.
Gibs are freshly set as per specs in BOSS maintenance manual.
Angular contact bearings holding ball screws appear to be
properly preloaded.

Any explanations for this?

Scott



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Polaraligned"
<polaraligned@...> wrote:

>
> I have a BOSS 4 that I have just reconditioned
> (with the exception of the ballscrews). Now I
> am measuring .003" in the Y and .005" backlash in
> the X axis. Quill has about .004".
> Is there a way to adjust the backlash on these
> BP ballscrews?
> This website says all machines have some sort of
> backlash adjustment.
>
> http://cncwiki.eriskouma.com/cncwiki/backlash.html
>
> Anyway, I called about 7 ballscrew rebuilders. I
> had one guy tell me that I would be better off
> buying NOS screws as there were so many made. ???
> Most saying a full regrind is about $700 per axis.
> And finally Esco Machine in Texas said that because
> my backlash is not that bad, he would give them a
> light grind and put oversize balls in for about
> $350 each. Tempting proposition.
>
> I am running Mach 3 and I don't think backlash
> compensation works all that well.
>
> Any thoughts?
>
> Thanks,
> Scott
>