On Thu, 03 May 2012 21:24:57 -0500, Ignoramus302
wrote:

On 2012-05-03, Karl Townsend wrote:
My CNC control is great for rigid tapping up to 1/2 by 13 TPI. Never
did larger.

I need to do 3/4 vy 10 TPI in 4140. I only have a TG100 collet to hold
the tap. Do I need to worry about stalling the spindle and/or tap
slipping in collet? Both have bery bad outcomes on an expensive tap.


The tap would not slip in the properly tightened TG collet, but, a lot
of other bad things could happen, sucn as spindle stalling, gears
breaking, etc.

My own mill, I think, does rigid tapping by being "digitally geared"
between revolutions of the spindle and the vertical Z movement. If the
spindle stalled, I think, the tap would not break because Z movement
would also cease.

Maybe the same applies to your mill.

i

I did 3/4-10 in A36 plate in my mill, did it with no problem at all.
Back then I asked here and no one could give me an answer so I just
tried it.

Remove 333 to reply.
Randy