Drilling and tapping combined

Your subject said it all. Use a combination drill tap and do it it one operation. A sample product supplier here:

There is a thing called a "tapping head". It has a pair of clutches that drive the tap in when you press down on it, and it reverses the tap when you pull up on it. I use thread drills in this to drill and tap in one operation, but the sizes are much smaller, like 4-40 up to 10-32. I don't know if there are thread drills available in 1/8" NTP, but if so, then get a tapping head designed for that size tap and go to it. Procunier and tap-matic make a variety of these tapping heads. I have the Procunier CNC tapping head, which doesn't have overload clutches. Some of the manual heads automatically reverse when the torque reaches a limit.

Jon

These guys:

Your job is to shorten the 'drill' part to be much less than the ID of your pipe and modify the bit shank to match the collet of your tapping machine...

--Winston

and use a tapmatic tapping head or some other one like someone else suggested.

John

I don't understand you need to have that accurate of a location for the subsequent tapping. The thing is that the tap tends to center itself on the hole so all you really need to do is to insure that the pipe is reinserted with the hole exactly up. I'd just make a pin hinged on the fixture that goes down over the pipe and centers it and then raises for the tapping operation. I'll also note that NPT holes need to have a depth stop otherwise the tapered threads will be either too large or too small.

-- Yeppie, Bush is such an idiot that He usually outwits everybody else. How dumb!

Darryl You could use the tap drill combination tool that Winston proposed in conjuction with a tapping head, but the problem with most if the tapping heads is that they have some radial float and could wander off a bit from where you want your hole drilled. These tapping heads are not really designed to accomadate drilling of the holes. Another option while not cheap, but cheaper than a cnc would be to buy a drill press with a tapping cycle and run the Drill/Tap in a regular chuck. Grizzely has one for around $1100. A Tapmatic self reversing tap chuck would run you $1000-1200. I can't say anything about the grizzley unit as I have never used or seen one, just using it as a refernce.

Since this is a pipe thread, do these drill-taps include the reaming for the tapered hole?

It might be better to design a fixture that can quickly position your part, then drill, ream, and tap in 3 seperate operations.

T> > Hi,

Ah..Darryl? Why not do this in two operations. Set up your v block, then drill a chunk of wood for the OD of your pipe. Put in a hole at the top that intersects the big hole and drop in a nail with a spring under the head. Set this the proper distance from your vise in your mill so when you drill the hole, then slide it into the big hole and push the nail down into it and voila..you are now registered for the next hole. Drill your pipes and stack em up in the corner. When you have run as many drilled as necessary..simply run them again, but push them from the block to the mill vise, each is properly registered and you simply tap em, registering each with the nail before closing the vise.

The other method would be to cough up $500 or more for a Burgmaster

Which is a 6 spindle drill press. Set up on spindle with the drill, the other with a tapamatic or similar and go for the gusto.

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

a good used Tapmatic, Procunier, etc etc should cost about a $100.

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

I have a 6 head drill press for sale. I could even throw in a tapping head.

========================= Why do you need two spindles?

Set up and drill the "many" parts, and put these in one or more tote pans, 55 gallon drums, etc.

Change out the drill/chuck and install the tap head, without moving the fixture in relation to the spindle [up/down OK]

Put the parts back in the fixture and tap.

Boring as hell, but that's mass production for you.

Unka George (George McDuffee) ............................. I sincerely believe . . . banking establishments are more dangerous than standing armies, and that the principle of spending money to be paid by posterity, under the name of funding, is but swindling futurity on a large scale. Thomas Jefferson (1743?1826), U.S. president. Letter, 28 May 1816, to political philosopher and Senator John Taylor

See my first post about a fixture with a pin register?

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

There ya go!

Commander or Burgmaster?

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

Buffalo Forge Co.

This isn't a Burgmaster where the tools pivot around the part. It's a gang drill press with 6 complete heads. For this operation, you would set up multiple stops. Drill the hole at one station, ream and countersink if you wanted, then tap.The tapping head would follow the drilled hole, so concentricity really won't be an issue. The OP could mount the part in a V block, then slide the V block from station to station quicker than a CNC could change tools.

Hey Unka George,

I think you missed a key bit of the wording in the OP. He is drilling and tapping these holes into round PVC pipe. He can't do what you suggest without doing something to index them first, and that negates the idea. Plus he would end up having to chuck them twice thereby losing production time.

The drill-tap sounded good to me, although depth might be a problem. Or a rotary table set up, where you drill say 36 pieces, change to the tap, tap the same 36 pieces (still in the same array location), empty the table and start again. Maybe even reload individually after the tap and step, so no loss of time.

Take care.

Brian Laws>>

Maybe I'm missing something; can you get a cheap drill press bolted alongside the mill, so you can (1) push your fixture into position under the drill press and do the hole, then (2) reposition it under the mill head for the tapping operation

Obviously you'd want the fixture to clamp for each operation, but a couple of DeStaCo toggles and some blocks for alignment is all it would take.

Relatively easy answer at a somewhat low cost too: TapMatic SPD5 or SPD7 with the "hard start" option. This will let you drap (drill/tap) combo tool a single hole. If you need to do more than one, put a multiple spindle head on the machine and then two or more SPD5/7 heads.

If you really have high production needs, you go to an automated system. See my sig links.

I sell them, probably discounted below TapMatic's prices... And will gladly quote you... But not here as that's bad form. It's bad enough I'm mentioning that I sell them.

One problem you are going to have is depth control on the NPT. I'd suggest moving over to a machine like the Grizzly G0521 which does automatic reversing of the spindle (you can then use the normal chuck to drap) at a pre-determined and programmable depth. Then, you can mount a multiple spindle head on there with 2+ tools to do many parts.

Regards, Joe Agro, Jr. (800) 871-5022

Basically, six drill press machines tied together with a common table / mount, right?

Not really made any more, but if you find them and they are in good condition, they can be quite useful!