Power Tapping on a PM25?

pretty sure I have a spare 1/4-20 spiral point tap. Would be no chore to stick it in an envelope and get it to NJ if you won't mind waiting for the post.
 
I've heard recommendations against using a keyless chuck and that a keyed chuck can be used as sort of a clutch dependent on how hard you tighten it.

But I've also heard of people having issues with the taps slipping in a keyed chuck.

Thoughts?

What rpm are you guys running when you power tap? Are you reversing by hand?
 
mattthemuppet2 said:
pretty sure I have a spare 1/4-20 spiral point tap. Would be no chore to stick it in an envelope and get it to NJ if you won't mind waiting for the post.
Click to expand...

matt: Thank you for your very generous offer. I was able to straighten things out with MSC and I just received my taps.
 
My mill has a variable speed motor so I'll be able to go down very low in RPMs.

I plan on trying a collet first versus a keyless chuck. I 'll have to see what the diameter of the tap is versus what collets I have.
 
Let me know how it goes. I'm going to throw a VFD and 3 phase motor on my drill press soon and perhaps even a foot pedal to reverse the rotation so I can power tap with it. Still looking for the best (cheap) method of holding a tap.
 
no problem, glad it got sorted out.

rpms you'll figure out, you'll have plenty of practice :) I typically go at 100rpm or so on my drill press - too slow and the tap slips, too fast and I can't stop the motor fast enough for it to actually stop when i want it to. I keep meaning to convert some cheap tap handles to hold taps in the drill press, get round to it one day :) Power reverse works fine.

no personal experience in using keyless chucks to tap, only that they're supposed to loosen when you reverse them. Typically only large taps or taps in steel slip in my drill press chuck. When that happens I usually take it out and use those first few threads to guide the tap in by hand. Large taps = LOTS of torque.
 
devils4ever said:
My mill has a variable speed motor so I'll be able to go down very low in RPMs.

I plan on trying a collet first versus a keyless chuck. I 'll have to see what the diameter of the tap is versus what collets I have.
Click to expand...
I use a collet on mine and have had no problems at all. Speed is very slow. Tom Lipton has a great little primer on power tapping on the mill. Here's the link:


Regards
 
Success! At first I tried the keyless chuck, but I had problems with the tap slipping. I measured the body of the tap at 0.254" so I put it in a 1/4" collet. It was a little snug, but worked. Actually, I had to tighten the collet quite a bit to keep it from slipping. I ran my mill at about 190 RPMs.

Interestingly, I found that the main power switch on the PM25 takes time to drain at low RPMs, so the spindle keeps spinning. However, if I turn the direction switch from forward to 0, the spindle stops instantly. This is very handy for tapping since I had to run the tap the full length to get 3/4" of material tapped.

Bottom view:
20200424_061309_edit1.jpg
 
You must log in or register to reply here.
Back
Top