On Tue, 12 Aug 2003 12:51:49 -0000, you wrote:
Maybe a few things made this less than a perfect test:
The extrenely light cuts kept the machine going at a constant speed,
within a couple RPM.
Even with this light cut, there was some chatter, which I couldn,t
hear but I can see on the photo. I need to read up on tool shape and
height for threading.
On the other hand there was some runout as I didn't take time to do a
truing pass before cutting.
I'm not sure the speed was right. The piece is 5/8" diameter and I
cut at 300 rpm with coolant, is that about right Steve?
A little bit slow maybe, for a 1/2"x20 UNF my old post processor would
have done it at 500rpm, with 3 passes at 10 thou, one at 4 thou and
one spring pass. (Total thread depth of 34thou)
That's with an insert, I have 10 thou set as max depth cut for
threading so it works it out itself.
Certainly I'm happy with it, and it's a start for more rigorous
tests, like taking a cut that does slow the machine.
May I ask the more experienced, what size cuts would you take cutting
20 threads per inch on a non-cnc machine?
At that diameter I probably wouldn't have run more than 200rpm
manually!
--
Steve Blackmore
