Deep hole tapping?

[btu44]

I have a couple of jobs I'm quoting that have some pretty deep threaded holes.

The first is a 6-32 .5" deep blind hole in pure copper, quantity 8 holes
The other 4-40, .375" deep through hole in aluminum, 8 holes

What I use to do is with a tap center, hand tap all holes.
Now I T/C tap head to what I believe is a safe depth and hand tap the rest.

But my tendinitis wrists have had enough. So whats the best way to deep tap on a Tormach with out the hand work, if possible?

Thanks,
Barry

[carlboe]

I have a couple of jobs I'm quoting that have some pretty deep threaded holes.

The first is a 6-32 .5" deep blind hole in pure copper, quantity 8 holes
The other 4-40, .375" deep through hole in aluminum, 8 holes

What I use to do is with a tap center, hand tap all holes.
Now I T/C tap head to what I believe is a safe depth and hand tap the rest.

But my tendinitis wrists have had enough. So whats the best way to deep tap on a Tormach with out the hand work, if possible?

Thanks,
Barry

Barry
I Tap alot of 8/32 holes 3/4 deep and do it in 3 or 4 steps. For blind holes I do that to but hold the last step short and hand tap them if need be.

Carl Boe

[TXFred]

On my tattoo machines, I have a 8-32 blind hole that needs to be bottom tapped. I use the tapping head to tap the hole with a taper tap. I finish the hole manually, using a bottoming tap held in the chuck of my Dewalt drill. I set the clutch on the drill to slip when the tap bottoms out. This lets me safely run the tap in under power with no fear of breaking a tap.

With #6 and #4 threads, the tap is more delicate. So you might want to try this technique on some scrap metal first.

Frederic

[GLCarlson]

OK, here's your little known machinist's lore of the day.

Somewhere, a long time ago, (and I swear I can probably find it...) I read that copper was best tapped using whole milk as tapping fluid.

If you try this, don't blame me if your machine rusts, smells like sour milk, or insists on being burped after every few holes....

I know I'm going to regret posting this. It was just too good to pass up.

[btu44]

Barry
I Tap alot of 8/32 holes 3/4 deep and do it in 3 or 4 steps.
Carl Boe

Is that like a pecking rigid tap cycle?

On my tattoo machines, I have a 8-32 blind hole that needs to be bottom tapped. I use the tapping head to tap the hole with a taper tap. I finish the hole manually, using a bottoming tap held in the chuck of my Dewalt drill. I set the clutch on the drill to slip when the tap bottoms out. This lets me safely run the tap in under power with no fear of breaking a tap.

With #6 and #4 threads, the tap is more delicate. So you might want to try this technique on some scrap metal first.

Frederic

Is the depth your going over 2.5 times tap diameter?

[carlboe]

Is that like a pecking rigid tap cycle?



Is the depth your going over 2.5 times tap diameter?

BTU 44

It is kind of like that I just set my cycle to do it 3 or 4 times. (like tap all of the holes and do it deeper next 2 or 3 times) that way I have time blow the holes clean.


Carl Boe

[TXFred]

Is the depth your going over 2.5 times tap diameter?

It's about 2x at a guess. I wouldn't have any concerns about going deeper with the same method, so long as I'm using a good spiral flute tap.

Also, since GLCarlson mentioned tapping fluid, I would like to recommend Boelube Paste. MSC sells it. It's a blue paste that does an excellent job of lubricating a tap. When hand tapping, I can feel the difference between oil and paste. A tub of it is $20 and should last you for years.

Frederic

[Steve Seebold]

It's about 2x at a guess. I wouldn't have any concerns about going deeper with the same method, so long as I'm using a good spiral flute tap.

Also, since GLCarlson mentioned tapping fluid, I would like to recommend Boelube Paste. MSC sells it. It's a blue paste that does an excellent job of lubricating a tap. When hand tapping, I can feel the difference between oil and paste. A tub of it is $20 and should last you for years.

Frederic

For tapped holes that small and that deep, I wouldn't even consider cutting taps. I would use use nothing but roll form taps. If you are leary of tapping your holes on your Tormach, then use a Tapmatic in a drill press, but I like the idea of starting the thread on the machine and finishing with a drill motor.

Steve

[btu44]

For tapped holes that small and that deep, I wouldn't even consider cutting taps. I would use use nothing but roll form taps. If you are leary of tapping your holes on your Tormach, then use a Tapmatic in a drill press, but I like the idea of starting the thread on the machine and finishing with a drill motor.

Steve

I agree that roll form taps are the way to go. Can you hand tap with them to a final depth? Have you ever used them on C101 copper?

But fortuately after talking with the engineer, he agreed that a 2x dia / depth is OK instead of a 3.6x ... problem solved.

[Proturn]

Hi in the past we have blind tapped M2 x 25.0mm deep in commercial Aluminum on our CNC M/C Center and had no problems and have tapped 1000.s of holes on the same Tap Rigid Tapping Mode and very high Revs to get the heat into the material around the Tap to make the material work too slow and the Taps will possibly jam and break. Copper can be tricky but you will have to make a few experiments to get the correct Lubricant I would start with Rocol paste as it has proved to be pretty good on other materials for us in the past, Ron

[Proturn]

HI I have just purchased a 1985 Takisawa TC2 as a project do up machine which has a alarm problem when the Spindle is asked to Rotate. We have been told that some of the or all of the parameters were lost and may not have been replaced correctly. Does any one out there have a machine of a similar vintage and able to supply a set of parameters that we can check against our machine. Ron ( r.pd.gill@xtra.co.nz )

[jrap57]

I use a FLEXARM brand tapping head with slip clutch tap adapters, the flex arm keeps the tap square , and the clutch only slips when the tap hits bottom of hole or the tap gets dull.