Re: [CAD_CAM_EDM_DRO] Using a tapping attachment with a CNC bore cycle

On Fri, 15 Feb 2002 19:00:48 +0000, Jon Elson <elson@...>
wrote:

>You'd better check the spindle HP requirements before tapping a 1/2 - 13
>hole in steel with a tapping head.

I was thinking I'd be OK. My reasoning - its a 3hp mill, running at
say 80 rpm - that should be around

(5252*3)/80 = 197 ft-lbs of driving torque. Even with 60% efficiency in
the drive train that still gives over 100 ft-lbs to drive the tap.

I've done 1/2-13 by hand - and it doesn't feel like it takes 100 ft lbs.
Is there a factor I'm missing that's going to sneak up on me? Usama bin
TorqueFactor?

The 1/8npt was to be in aluminum. I've done that by hand in times past
with a straight drill - I'll give it a try when the time comes and make
a report. It's clear I need to be sure I program and tap to the
specified depth accurately.

Fitch