On Sun, 7 Oct 2007 08:57:56 -0500, "Robert Swinney"
wrote:

Karl sez:

"The problem you're fighting is cutting speed. The SFPM on that small a
diameter is too slow unless the lathe is running at high RPM."

More'n likely if he is running that fast, the problem is the snaggle-toothed tool bit resulting from
crashing into the chuck at end of cut. 7/25.4 = 0.2756 inch is not a "small" diameter for
threading. I would seriously consider taking a close look at the helical angle involved. There may
not be enough relief below the nose of the tool.

Bob Swinney
"Karl Townsend" wrote in message
tanews.com...

apart from having the tool exactly on centre height, sharp edges to
the cutting tool, and experimenting with cutting speeds there are no
other tricks to getting polished threads at 7mm x 48tpi are there?
I'd welcome a description of how you get really schmick threads at
this size.


Karl


of course! gods I never even considered that aspect at this size.
hmmmm grind a wedge out of hacksaw blade to cock the tool over.
easy squeezy!

I'll have another go tomorrow night.

Stealth Pilot