In article , Alden Hackmann says...

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.

First off, what surface(s) are you hand-scraping, and to what
are they fitted?

I would suggest that you consider simply mounting the phenolic
blanks in OD jaws and and profile both sides, then mount on your
shaft or mandrel and take a skim cut across the OD to clean it
up.

The shaft you are using is pretty thin and flexible, that may
be where some of your chatter is coming from.

LE phenolic can be somewhat abrasive so if you are using HSS
tooling it will get beaten up pretty fast. Carbide if used
instead should be *un*coated as the coatings require a honed
edge and the phenolic really wants a sharp tool and fairly
large postive rake. My personal favorite for this is polycrystaline
diamond inserts from Valenite. I run the tpg221 sized ones
for composites and they last forever and give real sharp
edge.

You will also find that much of the aroma from turning phenolic
goes away when cutting with a very very sharp tool. I think
most of it has to do with burning at the cutting edge.

A beefier mandrel as suggested would be a good way to go.
This is how we used to make sheaves, three operations - profile
first side, profile second side, and mount on mandrel and
turn OD.

Jim

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