[kstrauss]

Isn't the actual spindle RPM irrelevant with rigid tapping? The infeed/outfeed should be controlled by the spindle rotation.

[shred]

Isn't the actual spindle RPM irrelevant with rigid tapping? The infeed/outfeed should be controlled by the spindle rotation.

Within the usual speed/feed limits of course. I've not done rigid tapping on the SL15, but have done lots of external and internal threads which should be very similar code-wise. You put in a short air-cut in front of the part to get everything synced-up properly.

My guess is it starts moving the axis at the 'book' rate, then modifies feed based on spindle encoder inputs, so you need enough encoder pulses for it to settle down. IIRC there's a tooltip in the conversational threading screen for that lead-in sync distance that suggests how long to make it.