[wwendorf]

Hi everyone, I am posting as I need to know what the smallest size tapping you have ever done with your tormach.

Has anyone ever done 0-80, and how does it work?

How about doing them as blind holes?

Thanks,
Wade




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[john robertson]

why do you need to know what i have done in the past , or are you asking if taping 0-80 is possible

[Gerry Sweetland]

He is asking what if any previous experience one may have in creating very small tapped holes, probably in hopes of getting some experienced advice on doing this procedure.
Why are you not understanding the question?
Gerry

[wwendorf]

Yes, I need to know of that
SmAll of a hole is possible. If so, how do you do it? What kind of tap? What kind of feeds and speeds? I also need to know about doing it in free machining brass.


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[MichaelHenry]

I've done dozens of 0-80 through holes in 6061 aluminum with a Procunier tapping head and spiral point tap in a manual mill and had no problems and a few dozen 3-48 blind holes in 6061 with my PCNC 1100 and Tormach tension-compression head with a form tap with no problems.

I'd think 0-80 would be doable in 360 brass and would probably try it out on some scrap before committing parts. I'd probably try form taps before other types, though you definitely don't want to be using standard hand taps. Don Clement likes Balax brand for form taps and others seem to like them as well.

Mike

Yes, I need to know of that
SmAll of a hole is possible. If so, how do you do it? What kind of tap? What kind of feeds and speeds? I also need to know about doing it in free machining brass.


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[CadRhino]

I have a t/c and when I called Tormach they said they didn't recommend it for blind holes. I was bummed.

[Steve Seebold]

How thick is your material? How deep do you need to tap?

You could probably do it if your hole is deep enough, you use a good lubricant and your tap doesn't hit the bottom of the hole.

[MichaelHenry]

I have a t/c and when I called Tormach they said they didn't recommend it for blind holes. I was bummed.

The 3-48 holes I tap with the basic Tormach T-C head are blind, but I'm drilling around 5/8-in deep and tapping 1/4-in deep or a little more. That's going from memory so the details could be a little off.

One advantage to tapping small sizes is the taps are generally fairly inexpensive, so you can usually afford to experiment a little.

Mike

[RussMachine]

CadRhino,
Did TORMACH say not to tap ALL blind holes, or just don't tap #0-80 blind holes?
Because I tapped several 1/4-20 blind holes, 1/2" deep with the T/C head, and it worked great.
I'm puzzled.

[SCzEngrgGroup]

There's no problem tapping blind holes as long as you leave enough room for the spindle to stop at the bottom BEFORE the tap hits bottom. That's purely a function of how quickly your spindle stops from tapping speed. At low RPM, with a good braking resistor, it should stop in just a few turns. If using spiral point taps, you also have to make allowance for the chips that will be piled up down there. For blind holes, spiral-flute taps, or form taps are a better choice.

Regards,
Ray L.

[RussMachine]

So maybe a good practice for blind holes would be drill point clearance plus two threads, to be safe. (If there's enough material)

[wwendorf]

Hmm, I may have to try this. I'll have to get some scrap material and small taps.

Wade

[FuriousGeorge]

I've never tapped 0-80 holes with a T/C head, but I do blind 2-56s all the time. Here is my method to figure out how to set my Z height with a new tap:

1: Drill 5 thru holes in some scrap of whatever material I'll be using
2: Tap holes to a depth of Z=-0.25"
3: Put screws in holes until I feel resistance and mark the exposed threads with a sharpie.
4: measure the difference and subtract that from the depth of a blind hole.

This will give you a good starting point with less broken taps.

Another word of advice, do NOT add a dwell time before your reverse your spindle. The M04 command has a sufficient dwell time built in. If you dwell too long the T/C's spring will become fully retracted, and the tap can break.

[CadRhino]

The Tormach person I spoke with said the didn't recommend it. I think others have a work around if one has enough depth.

CadRhino,
Did TORMACH say not to tap ALL blind holes, or just don't tap #0-80 blind holes?
Because I tapped several 1/4-20 blind holes, 1/2" deep with the T/C head, and it worked great.
I'm puzzled.