Re: [CAD_CAM_EDM_DRO] Re: Re: Re: Dead Grizzly speed control/VFD

John Murphy wrote:

> Mine is identical, so I'll try the same.
>
> Do you tap using CNC, or manually with your mill? I assume you would
> need some
> shaft position feedback (and control) to tap with CNC, or can you just
> start it spinning at
> the right rate and send it downward at the prescriped rate?

You can't do hard tapping this way. The tap will be broken for sure.

You can do tapping with a CNC tapping head. It has clutches that engage
for forward or reverse rotation based on the axial force on the tap. As long
as the spindle is feeding forward, the tap spins forward. When the spindle
feed reverses, the reverse clutch is engaged, and the tap is backed out of
the hole. This works fabulously well, and if you have a bunch of holes to
tap, it is just wonderful! The only trick is to make sure the spindle feed does
not exceed the proper feed for the spindle rotation. This could break a
tap. But, it works without a spindle encoder.

Jon