On 2009-09-26, Michael Koblic wrote:

"Bob Engelhardt" wrote in message
...

[ ... ]

On the lathe with an HSS bit & 100 fpm or so it *was* crappy. Bad
tearing. I tried a carbide bit at 400 fpm & it was pretty good:

http://home.comcast.net/~bobengelhardt/WeightBar.jpg

That's a finishing pass of about .003 DOC & .003 feed (the ruler is mm).

Once again it goes to show that YMMV,

Aaargh! Do no start me off! I just tried some carbide inserts with miserable
results. It seems Taig is too small for carbide even if cunningly sold in
1/4" tool-holders.

1/4" shank is too small for carbide insert tools. You need to
make a toolpost which will hold larger tool shanks.

And any holder sold with 1/4" shanks probably comes with the
cheap carbide inserts which are too thin, too weak, a poor grade of
carbide, and with no carbide anvils supporting the carbide inserts.

And most inserts are not really sharp enough for them to work
well in the Taig. Especially bad are the TiN coated carbide inserts, as
the coating dulls the edge a bit even if it was originally formed with a
good edge.

BTW -- if you want to see something which makes the Taig look
rigid, try an old Unimat SL-1000 or DB-200. Those use a pair of mild
steel rods as the ways, and they *bend* under cutting forces. This was
*my* first lathe at home. And I now have the Taig, which I consider
much more rigid -- though I also have other lathes, up to a 12x24"
Clausing. :-)

Good Luck,
DoN.

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