I have not had a tap breakage using Rigid Tapping on my equipment, that is until last night :)

The specifics are a #21 pre-drill, 10-32 spiral flute, 6061-T6 to a depth near the maximum flute length of 1" using flood coolant/lube.

Any advice before round #2

Thanks

Ken

Hello Ken, From days of old, back in 1995, I was the first programmer in the shop to use rigid tapping and it was on a Fadal none the less.

I'm sure the tooling has improved since then, but I do recall they had very specific taps designed for rigid tapping. Memory is that none of the taps were spiral flute, always straight 2 flute taps. The exception was the from threading taps, now that always made me pucker when we sent in a forming tap.

Confer with your tooling expert, I'm sure they can help out. Sorry, that is all I can add to help out.

Hey Ken,
My experience is that the best tool for that app is a forming tap. Usually tap breakage is from chip clearance issues. To use a forming tap you will also have to change your tap drill size.

I almost always roll tap (form tap) blind holes. Are you using a gun tap (straight flute)? Is so, you need to make sure you drill plenty deep for the chip clearance since these taps will push the chip down. You can use a spiral fluted tap which will "pull" the chip out back as it taps. At 1" depth you might have to watch the LOC of the tap though because the chip might pack the back side towards the bottom of the hole and break the tap. I would say roll tap it.

One other thing, are you rigid tapping with a floater or solid holder? Floaters will generally need a little more room on the bottom clearance.

I almost always roll tap (form tap) blind holes. Are you using a gun tap (straight flute)? Is so, you need to make sure you drill plenty deep for the chip clearance since these taps will push the chip down. You can use a spiral fluted tap which will "pull" the chip out back as it taps. At 1" depth you might have to watch the LOC of the tap though because the chip might pack the back side towards the bottom of the hole and break the tap. I would say roll tap it.

One other thing, are you rigid tapping with a floater or solid holder? Floaters will generally need a little more room on the bottom clearance.

Pretty much what this says
Spiral point for thru
Spiral flute for blind
Form tap for soft material and production work
With rigid tapping you can peck tap
I always hold in a solid holder
If it's a couple of holes just start the thread 1/2" and finish by hand.
A cordless drill is a great tapping machine as well
Oh yeah - my VMC is a Fadal (not that it should make any difference)

Guys this has been very helpful, got forming taps on the way.

Thanks for all the input, a friend also called and suggested that I decrease the spindle speed which automatically adjust for correct feed speed, especially for such a deep thread using a 10-32 and also was in complete agreement with the form tap usage.

Ken