Tag Archives: Rigid tapping without rigid tapping – WTF?

Rigid tapping without rigid tapping – WTF?

This morning, and for the second time in recent memory, one of my guys forgot what he was doing and put a tap in a ordinary ER collet chuck in one of the old machines that doesn’t have rigid tapping.

Both times the holes have come out perfect and I’ve felt like a fool while lecturing him how critical it is to use a tension-compression holder in this machine.

This morning it was a M16 in steel, last time it was a M12 Helicoil in 6082T6. The M16 I can kind of understand, but the M12 in aluminium surely should have stripped the threads or cut them oversize – but it didn’t.

What gives??

Machine is a 1992 Hurco BMC25 / Ultimax 2 control. The Yaskawa spindle drive supports rigid tapping, but I know for fact that the control doesn’t.

I’m not about to go and put all the taps in rigid holders for this machine, I’m just curious.