"Bob Powell" wrote in message
s.com...
"Michael" wrote in message
...
I have a well used Enco Mill Drill which is made by Rong Fu in Taiwan.
I
think it's the model RF-20. The spindle on it has a bit of play and
tends
to produce lots of harmonics and chatter when boring or using the side
of
an
endmill to cut. I don't know much about these so this may be something
that
can be addressed by turning a spanner, or maybe it needs new spindle
bearings. If anyone has had to correct this on one I'd really
appreciate
any input on what the cause usually is and how to go about fixing it.
Thanks, Michael.

I have the identical machine, made in 1992.

I think the spindle bearings are ordinary ball bearings, like standard
sealed electric motor bearings - nothing exotic. In the realm of $50 for
an
identical Chinese replacement.

That said, the quill bore is likely to wear faster than the bearings. Do
you do all side cutting with the quill securely locked? When boring, the
quill lock should be cranked enough to drag. Accelerates wear but
improves
the finish.

It's also possible that the upper spindle bearings are at fault, as they
take the side load of the belt but are not as beefy as the spindle
bearings.

The table ways/gibs are also pretty rough, I found it difficult to get a
perfect gib adjustment and so have always cranked the gib locks until the
table drags a bit when making a finish cut. Again, accelerates way wear
but
improves finish.

Goes without saying whichever axis is not moving should have its gib locks
tight. For boring, both axes.

Bob

Sorry, I just RTFM'd a bit late. Oops.

According to the manual they are grease-packed taper roller bearings, the
upper is a 30205J and the lower is an E30206J.

Adjusted by a pair of locknuts at the top of the quill.

The manual says to loosen the bearings if they run too hot, tighten if the
surface finish is "rough". It doesn't say how, but it looks like you remove
the rack pinion (i.e. the quill feed shaft) and the quill just drops out the
bottom of the head casting. I don't know if you can get to the bearings via
any of the access plates, may just have to remove the quill.

I can say from other experience, if the quill doesn't heat up when running
at top speed, the bearings are too loose.

Mine has behaved so consistently, I never would have guessed taper roller
bearings.

Bob