Subject: Atlas 12" chatter problem

From: [email-masked] (Greg Lewis)
Date: Sun, 19 Feb 1995 00:18:51 GMT

I can't seem to get rid of the chatter in my Atlas 12" lathe. Here's
the setup: 6" long 5/8 dia 1018 crs bar extending 5/8 from a 6" flat
back 3-jaw chuck. I can't take a cut without serious chatter. Even if
I use the old adage "a slower speed and a faster feed" I can still see
the chatter in the work even if it isn't audible when cutting. I'm
using a KRF toolholder with 1/4 square newly sharpened HSS toolbits
set on dead center with a height gauge. I've tried three different
toolbit shapes that have all worked for me in the past. The compound
rest is locked down tight, the cross slide gib is set so it will
barely move, ditto the carriage gib. Checked and tightened the spindle
bearing pre-load to almost twice what the book recommends. There is
nothing left to tighten and no detectable backlash anywhere except in
the cross slide, which is within normal limits when compared to other
lathes. This is a very low mileage machine, bought from the original
owner who used it only a half dozen times.

I have heard that these lathes are prone to chatter. What experiences
do you folks have with these machines? I am at the point where I'm
thinking of selling it and finding something else. Comments?

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