Background info:
I have started a job duplicating posts that are 8x8 by 31 inches. The
posts are made from 8/4 poplar that is glued up. These posts are
hollow on the inside and have about a 4 inch square hole running the
full length. I am using a Oneway 2436 and a Vega Pro duplicator to
turn them. They are held on the lathe with oak end caps. The
headstock end has a face plate screwed to oak end cap. Seems to work
well for most of the posts.

The problem:
Most of the posts are turning very well with minimal vibration and
look nice. I have to keep the lathe speed up to about 1500 rpm for the
duplicator to work right or it does a crappy job. I tried lower
speeds and the results were very bad. I called Vega and they
suggested at least 1500 rpm. I get a little vibration when I first
start but nothing I can’t live with.

The problem is that a few of the posts are having unacceptable
vibration. Even at lower rpms the 900 pound lathe is dancing around
the workshop. I am pretty sure that the individual pieces of poplar
used to glue up the posts are not all the same density and weight.
That makes them heavier on one side. Se even if I roughing those
particular pieces manually with a gouge first, it does help because
the wood is still heavier on one side than the other.

Any suggestions?
Has anyone run into this kind of problem before? I have thought of
using some kind of weight as a counter balance but I don’t know what
kind of weight could be used that would be able to be attached to a
post and I am not sure how to find out for sure which side of the post
is heavier or how much weight should be used.

Thanks for any ideas,
Ted J
thelatentlog.com