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On Tue, 15 Nov 2011 17:16:48 -0800, "PrecisionmachinisT"
wrote:


wrote in message
. ..
I posted a while back that I might be buying a Fadal mill and running
it from a phase converter. Well, I'm buying it. I'll write the check
tomorrow. It's a model VMC-15 and has rigid tapping so I guess I'll
need that parameter changing info. Also, just what is the advantage of
rigid tapping over tapping heads?
Thanks,
Eric

The main advantage of having rigid tapping is that it allows you to use
standard drilling collets and chucks instead of having to buy a bunch of
additional specialty tooling that is only useful for tapping.

So all the compression/tension tap holders and collets I'm also buying
are not neded? I can just hold the taps in ER collets for example?


You would still do well to buy at least one rigid or floating chuck and a
handful of adapters to use wherever it is advantageous to drive from the
square tang--but mostly they are only needed for larger diameters...say 1/2
or so and above and in tough materials like stainless where high torque
requirments might otherwise allow the tap to slip.

That said, you'll usually also be able to better control thread tolerance
limits with tap adapters because they typically allow for the tap to wiggle
a slight amount on the radial axis and so it tends to center itself instead
of being horsed into the material, producing a loose hole...

--something to consider for instance if you are doing a aircraft work in
aluminum where 3B fits are the norm.