Re: [CAD_CAM_EDM_DRO]Backlash & Wobbly Spindle on my Bridgeport

Marcus & Eva wrote:

> Clock the inside of the machine spindle in a couple of places inside the
> taper.
> That is the ONLY way to ascertain if the taper is worn out.
> If the spindle taper checks out OK, you know the toolholders are at fault.

If the spindle checks out and the runout is in the tool holders, be sure
to check the holders twice, 180 degrees apart. That is remove, rotate
180, reinsert. I found on a Wells Index machine once that we had to mark
certain holders and insert in the same orientation to keep runout to a
minimum. If the spindle is worn, there is an outfit in Oregon that
rebuilds Bridgeport spindles. They regrind the taper and spec .0002
runout. I'll bet they can regrind a #30 taper as well.

Regarding the ball screws, if the problem is consistent across the
length of travel you might want to spend a bit of time checking out the
thrust bearings and bolts that secure the ball nuts. If something is
amiss here it will look like backlash.

Jon