On 2011-03-14, Karl Townsend wrote:
On Sun, 13 Mar 2011 22:50:42 -0500, Ignoramus858
wrote:

On 2011-03-13, 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, what about ER type collets?


Should work just as well. However you do it, a complete set of collets
is real handy.

I will try to get or make up a set. I have quite a few ER-16
collets. I also have a floating tap holder, which I do not really
need, but it is nice to use as a belt and suspenders approach.

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?

I know that RT uses index pulse to re-enter previously tapped
holes. That should do what you are talking about.

i
If you do much tapping, you'll long for these enhancements.

I can write a peck tappign routine, it is not a big deal. What is that
R plane?