I had 44 holes to tap to M5. This was my first try to do all CNC tapping with no chip clearing. I normally do one at a time with the quill and clear the chips and move to the next hole. The M5 roll form tap worked well. I don't know the exact RPM .When I get my RPM gauge back I will update.

Sorry I didn't see the second half of the video did not focus well.

To set the proper speed I was not clear in the video. For a given RPM you need to adjust the feed over ride in Mach 3 to slow down the retract to the proper amount. This slows down your fee rate too.

On my mill the Z feed is set to 70 IPM. I wanted a feed rate of 17.5 IPM and a retract of 35 IPM.

To get a 35 retract, I reduced the feed over ride to 50% and set the feed to 30 IPM in Cambam for the drill op.

Then all I had to do was find the correct RPM. I did this by using a long M5 bold chucked into my tapping head and test tapped into a test hole. Watching the sliding shaft part of the tapping head you can see if chuck is gaining or loosing distance. To be really fancy you could mount a indicator. I set speed by setting the frequency of the VFD which ended up at 47Hz.

For feeding is is best to have the tap lead a little. For retract its the same. The tap should lead the tapping head slightly to prevent pullout.

If I re do drill chuck mount so it wobbles less I could up the RPM even more.

Hope that helps.

Thanks for watching
Dave