In thread "18 tpi?" started Dec 7 IIRC, Don Nichols asked, quoting courtesy
Google's beta reader,


I took a closer look at page 28. The tool holder does hold a tool across or in
line with the feed. But no, you can't set the tool square to the work using a
traditional symmetric threading tool, and feed along a flank. I'm thinking of
using a T6 Diamond Toolholder.

------------------quote

Hmm ... I don't have one of those. Does it happen to be at just
the right angle to make a 60 degree included angle on the tool bit? (I
saw where you negated this idea afterwards -- because it is too big for
the toolpost's slot.


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Yes, it is a trapezoidal cross section tool steel bit clamped near vertical,
canted outward for clearance, and sharpened on the top, which is the end of the
bit, with an included sharpening jig. With a Scary Sharp setup, it's capable of
very fine work.

With the cross section and canting, it cuts 60 form, possibly other forms, and
is adjustable for all facing and turning cuts. Quite a handy tool. It will work
on HF's mini lathe which *likely* accepts Unimat SL-2000, Unimat One, HF
8-in-3, and HF mini 3-jaw tooling at M12x1 threading, having 1/2 capacity
toolpost. I believe Sherline offers a metal four jaw with M12x1 now. I digress.

http://www.harborfreight.com/cpi/cta...temnumber=4019

http://www.harborfreight.com/manuals/4000-4999/4019.pdf

Nice little piece of cast iron with a DC motor. Doesn't thread. $209.99. Wide
range of speeds.

7/16 x 1/2 is the smallest Diamond T6 tool shank. It's a lot like the old
forged tool holder but adjustable and you can sharpen the *end* of the tool.
That's crucial. You would not believe, well, no you would believe, because you
all know what a really sharp tool can do, and this tool holder lets you keep
that tool _sharp_.

I'd set their bench grinder accessory aside and make a block of oak to fit the
bit, lapping the end Scary Sharp with 600, 1200, or so grit SiC paper, maybe
even finer. We had a thread here around six months ago about turning copper,
and it wasn't about commutator work, but on commutator work, Scary Sharp is
what you need, and milk as a coolant, whew, stinky if you don't clean it up,
but you can get fine results with a sharp tool and the right, rather large
rake, where for threading steel, a really sharp tool helps reduce that awful
tearing you get in steel that ruins the finish and sometimes requires filing,
which reduces accuracy.

OK, so that's what I know about the T6. Cost about $99.

My aplogies for any spelling errors. I'm using the conversational newsreader in
AOL.


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