Tapping advice

[tbaker2500]

Hey smart people! I have never done CNC tapping before, but I'm looking into it for a new production part I'm running on my 1100 series 1. I could use some fairly basic advice.

My part is 6061-T6. It has 5 4-40 blind taps. .280" hole depth, ~.13" needs threads. Then 3 10-24 blind taps, .6" deep with ~.25" threads.

1. CNC tap or hand tap? I don't own any CNC tapping heads at the moment. Do I save enough time to justify a head?

2. Tormach doesn't recommend their auto-reverse tapping head for blind holes due to chip buildup. What about a fast spiral or a thread forming tap?

Thanks
Tom

[beanbag]

http://www.cnczone.com/forums/tormac...45394-tap.html

[tbaker2500]

Thank you. I had been reading that thread. However, I have a series 1 machine so I can't use a T/C head. Can you use a thread forming tap on a reversing head?

[beanbag]

It depends on how many parts you need to make.
If it were only a few parts, then what I do is hand g-code in g0's to all the hole locations and put in a M1 pause. Then I put my tap wrench into the spindle and tap by hand, occasionally using the wheel or keyboard to extend and retract the spindle.

If you didn't feel like spending all the money on a tapping head, then I would build a spring loaded tap holder thing.

[Don Clement]

My part is 6061-T6. It has 5 4-40 blind taps. .280" hole depth, ~.13" needs threads. Then 3 10-24 blind taps, .6" deep with ~.25" threads.

1. CNC tap or hand tap? I don't own any CNC tapping heads at the moment. Do I save enough time to justify a head?

Tom

For me I have found that for tapping just a few holes that hand tapping can be very quick when using a Fisher micro tap guide. Fisher Machine Shop Pee Dee Wires and Tap Guide Shown here is hand tapping a 10-32 hole using the Fisher micro tap guide in the Tormach manually using the jog shuttle controller. The Fisher micro tap guide has ½” travel so it’s really quick and easy if the holes are not deep. You don’t need a reversing tapping head or have to write G-code to use either.

[tbaker2500]

Ah, learned another thing today. CNC mounted tap guides!
Thanks

[Wog]

Another option is just the old fashion hand tapper. You can find them for around $100.
I have both a Procunier-style and a Tapmatic reversable tapping head for my Tormach series 1, but find myself using the hand tapper for most holes in flat surfaces. Great for blind holes.
If you have a bunch of through holes to tap, just add a power drill to the top in place of the handle.

[tbaker2500]

I have to admit, I hadn't seem a framed hand tapper like that. Excellent solution for hand tapping!