Re: Bridgeport Ballscrew Backlash

I'd be shocked if that Boss had worn out ball screws. Did you check
the backlash in the middle and at both ends of travel? Are you using a
test indicator to see what the endplay is in each axis when you
push/pull on the handle?

The ways on a Boss are far wider than stock. Is the flaking or chrome
still uniform in appearance all over each way surface?

Make sure the ways and ballscrews are extrememly well lubricated
before you measure endplay or backlash. Dry machines can cause
intermittent results that make tracking them down a bear.

Mike



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

>
> 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
> >
>