OK, so here's the situation: We make this weird instrument (see www.hurdygurdy.com). It has a rosined wheel, turned by hand
by the player. For about a year we've been making the wheel from a linen-filled phenolic, which is wonderful - no moisture
sensitivity, much less machining time. The only downside is how long it takes to scrape the wheel so it has no runout.

So at breakfast my wife asks me why the wheel always needs to be scraped, i.e. why doesn't it come from the lathe with no
runout - and I have to say I don't really know. I then postulate that it's because the wheel and shaft inevitably exhibit
some chatter when turned on the lathe. and I wonder what I can do about it.

The shaft is about 7" long, and the wheel is 7" diameter x 3/4" thick phenolic. The shaft diameter is 5/16", O-1 drill rod,
held between a 5/16" A3 collet and a live center. The wheel is about 5" from the wide end (in the collet) mounted on a
threaded region, supported by a collar. I'm using a South Bend 9".

Any suggestions for how I might turn this material with less chatter? For example, what side rake and back rake angles are
best for phenolic resin? A slow speed seems to help, but doesn't eliminate the problem. The shaft would still be relatively
"floppy". I could turn the wheel on a thicker, heavier shaft, but then it wouldn't be being turned on the actual shaft that
will be used.


Your help appreciated, as always,

Alden


--
Alden F.M. Hackmann
Web: http://www.hurdygurdy.com/hg/hghome.html
"Beati illi qui in circulum circumeunt, fient enim magnae rotae."