On Saturday, August 25, 2018 at 2:09:52 PM UTC-4, wrote:
I have had to relieve the diameter of tap shanks many times in order
to tap deep holes or to cross a bore and the like. This morning I
needed to reduce the shank of a 5/16-18 tap. The job required that all
but about 3/8" of the shank diameter needed to be turned down. This
meant that in order to do the turning in one chucking the end of the
tap needed to be supported. The tap in question was a spiral point
tap. So I used a live center for support. I put a .25 thick piece of
aluminum between the point of the center and the tap. Then, with the
spindle turning, I cranked the tailstock quill forward until the
center and the tap points had both made pretty deep depressions in the
aluminum piece. I used a coated threading insert to turn down the tap.
255 RPM and .004" feed. The material was removed in one pass. I
plunged the tool into the work where the cut would not be an
interrupted cut. Then fed away from the chuck by hand to remove the
incomplete threads. This part of the cutting was an interrupted cut so
I wanted to feel the cutting. After removing the incomplete threads
the cut was reversed so that the tool was feeding towards the chuck.
The operation worked quite well and the threading insert still looks
good. HSS taps are hard but coated carbide is much harder.
Eric

Nice turning, Eric. My world is somewhat made of custom modified tools. But were you holding your breath while doing this?

I'm currently in the Sun Valley Idaho area for work, and the smoke from various forest fires is pretty horrible. I've been here a couple of times before and I know there have been days in the pst week when the visibility is way below five miles. Today was pretty good, though, and I got in some good views of mountains and wildlife.

I understand though that up in your neck of the woods, it's really bad. are people doing anything different to cope with it? I was surprised here that there aren't people wearing at least particle masks - my mouth has taste like smoke for a week.