03-29-2015, 08:03 AM
Ed,
You shouldn't have any fears about power tapping, as long as your spindle reverses in a reasonable way. Some VFD's need tuning to get them to reverse the way a 3-phase motor on true 3-phase power does.
Of course using true machine taps is critical. Try power tapping with a 4 flute hand tap and you can fully expect disaster.
I know that some folks have "tapping machines" such as those hand crank ones, or tapping heads and they work fine. They need no reversing spindle. In my shop I'm limited in space so my drill press which could use a tapping head is outside in the "wood shed" and rarely gets used. I don't have room on a bench or floor space for a hand tapping machine, so power tapping is my fast and easy solution. I'm very comfortable with it, don't have to adjust torque settings of a tapping head or crank the knee down low to use one. It's not for everyone.
This test was to see where I'd find the limits of what my machine (and I) can do reliably. I now believe I could power tap up to a 7/8-9UNC in a through hole and this 3/4-10 would be the limit in a blind hole.
You shouldn't have any fears about power tapping, as long as your spindle reverses in a reasonable way. Some VFD's need tuning to get them to reverse the way a 3-phase motor on true 3-phase power does.
Of course using true machine taps is critical. Try power tapping with a 4 flute hand tap and you can fully expect disaster.
I know that some folks have "tapping machines" such as those hand crank ones, or tapping heads and they work fine. They need no reversing spindle. In my shop I'm limited in space so my drill press which could use a tapping head is outside in the "wood shed" and rarely gets used. I don't have room on a bench or floor space for a hand tapping machine, so power tapping is my fast and easy solution. I'm very comfortable with it, don't have to adjust torque settings of a tapping head or crank the knee down low to use one. It's not for everyone.
This test was to see where I'd find the limits of what my machine (and I) can do reliably. I now believe I could power tap up to a 7/8-9UNC in a through hole and this 3/4-10 would be the limit in a blind hole.