CNC threading: tapping head or T/C holder ?

(Moderator note: This post is getting very boderline for this group. This group is for hobby issues, not productions shops. We also focus on the how to make the machine and not the how to use it. So, I am releasing this message with the warning that if it gets into a big discussion of issues not relavent for the home shop or focused more on the details of running the machine than making the machine it will be considered off topic and people continuing it will be moderated)

Hi people.

We've got thread milling working really well for the larger threads that
we need. (ie <5/16") We now need a CNC method of automating our small
thread cutting ie #6 through to 5/16", maybe 1/2" if it was
faster/easier than thread milling.

Should we use a tapping head or a tension/compression tap holder ? Our
mill has a G33 cycle, but it might be difficult to get a spindle encoder
on it. I can write a custom canned cycle for tapping if it need be.

On average, we cut a dozen threads per day. Thread milling has really
taken the heat off for the big threads.

A typical application is to tap 60+ 10-24 holes, 1 deep, into mild
steel. Another application might be to tap several holes of different
sizes on the same work piece, ie 5/16", 1/4", etc. We need to tapping
tool to be convenient for one off threads. Some of our holes are
bottoming, some through. We rarely tap harder steels such as SS or
4140. We sometimes tap aluminum.

One thing I am worried about is tool height. All mills have limited Z
axis travel and by the time one gets a vice, workpiece, tapping head and
tap into the equation, space is generally pretty tight.

Which CNC tapping method would you chose: a tapping head or a tension
compression tap holder ?

--
Kim Lux <lux@...>