On Mon, 27 Sep 2010 21:00:46 -0500, Ignoramus21149
wrote:

On 2010-09-27, Karl Townsend wrote:

And, you won't believe what a MESS this will make, if you ever mess up
and have the spindle running at the wrong speed for the calculated
feedrate. been there, done that!

What will happen, it will tear the tap out of the collet?

Anyway, obviously rigid tapping, optionally with the floating holder,
is the way to go.

i

I predict that rigid tapping will be a priority for you AFTER you've
broken a few taps off and ruined the part. BTDT

I think that I understand the basics of rigid tapping: the Z axis
follows the measured rotation of the spindle. When the spindle rotates
steadily, I would think that it can be done pretty well easily.

But how does rigid tapping handle reversal of the spindle, when the
spindle speed changes very rapidly, from forward to stop and to
reverse? The Z speed also needs to be adjusted super sensitively?

i

Its called electronic gearing. For every X encoder counts, move Z axis
Y encoder counts. Or the Z axis is slaved to the spindle. So, when you
stop the spindle, Z motion stops. When you revese the spindle Z moves
negative.

Karl