On Mar 13, 11:58*am, john wrote:
Karl Townsend wrote:
On Sat, 12 Mar 2011 23:03:37 -0600, Ignoramus25538
*wrote:

My CNC mill does rigid tapping and it is great and easy to do -- just
one "one liner" like this

* * G33.1 Z[-0.5] K[1/24]

would rigid tap a 24 TPI thread from the current point to the depth -0..5.

Easy and powerful.

It even works great with fine threads, but I have a problem with
coarse threads. I hold the taps in a Jacobs drill chuck. The chuck
cannot hold a coarse tap, like 1/4-20, the tap slips in the chuck. The
result, is holes that are partially tapped and a slipping tap. Not the
end of the world, but I want to do better.

What kind of tool holder should I use for this rigid tapping? Would
colleted tool holders help with this?

i
A drill chuck is a REAL POOR choice. Slips easy and isn't on center. I
normally use my TG100 collet holder and the right diameter collet.
Tighten up real good. Slipping is a BAD thing.

Karl

P.S. Does your control have Q for peck tapping? Or R for start plane?
Is it modal so you can just enter points to tap after first command?

Karl

The idea thing to use is the TG100 collet holder with a tap collet.

John

ER tap driver collets have squares in the back to grip the the tap -
thus:
the no spin zone
the broken tap starts here

--
~g~