On 2011-03-13, 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?

Not sure with a mill and rigid tapping, but the chucks on the
TapMatic tapping heads have a combination of a Jacobs Rubberflex collet
to hold the tap on center, and a pair of steel plates in the back of the
collet which are tightened down on the square end of the shank to keep
it from slipping in the collet. The two plates are joined by a setscrew
which is tapped left-hand on one end, and right hand on the other end,
so it retains centering as it closes.

Places like MSC sell the tap collet as a separate item, and you
might purchase that.

Hmm ... I don't find them with a quick search -- discontinued?
If so -- what will TapMatic use in the future?

On eBay -- here is an example -- but the price is scary:

# 130496833235

What would be really nice to have would be this mounted on a NMTB-30
taper toolholder.

Good Luck,
DoN.

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