On Sep 13, 4:00 pm, "Harold and Susan Vordos" wrote:
"Jim Wilkins" wrote in message

ups.com...

On Sep 13, 3:07 pm, Alex wrote:
...
The runout means you can't bore a perfectly cylindrical hole using the
quill feed but you may be able to by locking the quill and raising the
table, which is what I have to do. Used machines require a little
understanding, no big deal. How is the runout with the quill
retracted?

jw

Do not confuse runout with deflection. That a quill moves under a given
load doesn't mean it won't run a circle. Running a true circle relates to
the bearings, not the quill fit.

Harold

On my 50-year-old mill the lateral deflection increases as the quill
extends and its upper and lower supports approach each other. The
clamp can remove play from only the lower support.

When I bore a hole with the quill feed the hole tapers slightly inward
with depth as the quill deflects away from the cut, and a shaft that
fits the mouth of the bore jams a short ways down. If I bore with the
quill retracted and tightly clamped, by raising the knee, the shaft
fits equally all the way down.

The taper is probably no more than 0.001" / 1" but I wanted that
hydraulic gear pump bearing to fit as well as I could get it.

jw