Tapping gun questions

I need to tap a couple hundred 10-24 holes through 1/4" 6061 aluminum, and the project is way too big to put onto a mill or drill table. To speed this project up I am considering getting either the Bosch electric tapping gun or a Sioux pneumatic tapper (model TPA9C-420).

So my questions are:

1) Neither tapping gun appears to provide any sort of clutch function, and the pneumatic tapper appears to hold the tap rigidly. If I use either of these tapping guns, am I likely to break a lot of taps? I suspect either gun would be way faster than doing this by hand but if I have to add time to deal with broken taps there is probably no overall time savings.

2) what is the typical air consumption for pneumatic tappers? All that I have seen are speced at around 30 cfm while running at full speed but I dont know the typical % time the air motor is actually running. My air compressor is only a 17cfm unit so I'm wondering if it would be running constantly or even falling to keep up with an air tapper.

3) any comments re: which of these tappers is better for this sort of tapping? Or is there some other tapper I should be considering? I almost always use small taps (up to 1/4") in either 6061 or mild steel.
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How about a big (18-24v) cordless drill with a clutch and a home made tap guide. Get a handfull of Nachi taps. I've done similar in such.

Reply to
Tom Gardner

I have used this one for millions (OK, many thousands) of taps (mostly M6; about equal to 1/4") and maybe I broke one or two while using it. The other taps just went dull.

I can *highly* recommend it. But it ain't cheap. Bigger model available.


Reply to
Nick Mueller

Through holes are easy. You can run flat out till through, flat out to remove. The holes you describe could be done with a cordless drill if you were so inclined.

Whether you break a lot of taps is going to depend on your ability to keep them running straight in. A tapping arm may be worthwhile to you, or not.

I have used a Sioux reversing 3/8 drill to tap with, but with larger taps than you are using. Fast. Power in, then thumb the reverse button down, without coming off the trigger.

I have my doubts that you could outrun your compressor, tapping. You would need to get up well past a 50% duty cycle with the tapper to do so.

Cheers Trevor Jones

Reply to
Trevor Jones

I have no experience with the tappers you've asked about, but for a couple hundred holes a good reversible pistol drill will work just fine. I've tapped thousands of 10-32 holes in the 1/8" mild steel back panels of NEMA enclosures while building control panels.

My preferred drill for the job is an older Milwaukee with a lever for reversing above the trigger, but any drill with a control that's easy to operate without changing your grip should do the trick. Use a gun tap and apply a solid tapping compound (stick wax, Boelube, etc.) to the tap every couple holes.

Ned Simmons

Reply to
Ned Simmons

I use a small (1/4" chuck) inexpensive import pneumatic drill with a reversing button on the top, never broke a tap. It has enough torque to tap holes but not enough to break a tap #8 or larger. Got the idea from seeing a guy tapping hundreds, maybe thousands, of holes in a big aluminum object in a machine shop. As others have said, use lube.

The air drill is also nice because it's far less weight than an electric drill and it doesn't get hot with extended use.

Reply to
Don Foreman

Hardly seems worth it to buy the power tool just for this job, unless it's one you'll be doing regularly.

How will you drill the holes, and how square do they have to be? You might even sit a bench model drill press right on the aluminum sheet and drill that way.

A hand tapper (stand) would at least ensure that the tapping was square to the work. It would also keep you from breaking taps.

John Martin

Reply to
John Martin

Variable speed drill that is ez to reverse. If squareness is an issue, use a tapping block to get lined up. After the first few, I think you'll get an appreciation for the angle of the dangle and be able to do without it.

I had a cordless drill with a bubble level that indicated straight and level once upon a time. That was sweet for punching panels.

Wes S

Reply to

I use my 18V Milwaukee cordless and a spiral fluted tap for aluminum

Spend your money on good taps and use a good cordless drill

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I'm not a professional machinist.

I have had very good luck with these:

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up in a battery drill. You can back the torque setting off if necessary. Sure is nice to have reverse. If you let them go full depth you get a slight chamfer. These bits don't do well in heavy steel, but are great in aluminum and light stuff.

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