Author Topic: Tapping a lot of holes (Read 12940 times)

Brass_Machine · « **on:** April 12, 2009, 11:05:29 PM »

So I have a project coming up that is going to involve tapping a lot of holes. Think minimum of 600 holes... Plus maybe (more than likely) 3 to 4 times that and then some further down the road.

So the big question... what is a good way to do this? I really don't want to tap these by hand, but I don't have the CNC capabilities.

Maybe something like this Tapping Attachment?

Ideas? Help?

Eric

bogstandard · « **Reply #1 on:** April 12, 2009, 11:58:09 PM »

Does that include the drilling as well Eric? The reason I ask is that you can buy taps with the drill point already on, so it drills and taps in one go. Not the cheapest of things, but something to consider if you are going into production. Basically you are halving the production time.

For power tapping, those auto heads usually work very well, about 5 to 10 seconds for full insertion and extraction by hand feeding. I have never used them with a drill tipped tap but I don't see any major issues.

But highly recommended are good quality taps and cutting fluid.

Of course, it all depends on material and tap sizes being used.

If I have say 50 to 100 small items to be tapped, from 3mm to 6mm size, in up to 10mm thick mild steel, I will use my battery powered portable drill. As shown on my faceplate here,

http://madmodder.net/index.php?topic=422.msg1041#msg1041

Tedium is the main killer when tapping so many holes manually.

John

usn ret · « **Reply #2 on:** April 13, 2009, 01:04:03 AM »

Eric, we need some more info: material, thread sizes, hole patterns etc. as much info as you can provide. Some ideas to consider: HF is a good place to start for price and quality comparison. HF at the bottom followed by Enco. Grizzliy, Penn Tools, Travers up to and including $$$$$$.00.

Keep in mind that you will probably be using this tool again on the follow-on projects, therefore get the best you can afford as it will pay you back in reliability and ease of use. John's suggestion to use drill-taps is a good place to begin. If you are able to use the mill and use fixtures and jigs to enhance repeatability and reduce setup times. A good lubricant and ridgid set-up will help reduce tap breakage. For using a battery powered drill I personally only use 2 flute taps to cut down breakage.

Cliff

gilessim · « **Reply #3 on:** April 13, 2009, 03:40:11 AM »

Eric, many years ago in the UK, I sometimes gave a hand to a guy who had a business making brass earth wire connecting blocks, like the plastic "chocolate block" type but solid brass instead, each with 5 holes across and 5 pairs of 1/8" tapped holes on top for the screws that clamp the wires, they were held in hardened steel jig boxes, first drilling all the holes, then tapping with a small (very old) tapping machine that looked like it worked on the same principle as the attachment from your link, I was paid 25 pence for each one and going at it hard ,I could do 1000 in an 8 hour day, 10,000 tapped holes!, very boring (no pun intended!) but £25.00 was quite a lot in those days so it was worth it!, we used to have to change the drill bits quite often but I can't remember how long the taps lasted, anyway the tapping machine worked a treat and never broke down as far as I can remember, so I would give that one a try, it looks like a good price!

Giles

John Stevenson · « **Reply #4 on:** April 13, 2009, 06:50:00 AM »

I have tried the drill taps and to be honest not had much success with them.
If you look at one because they need to clear the chips they have larger than usual flutes which makes them weaker.

Another point is optium drilling speeds and tapping speeds are different so you have to compromise, usually running slower and hence the chances of breaking a drill / tap which is more expensive than either a drill or tap.

Last point is the tapping attachment whist very good are not really positive in location , they do have headache which allows the tap to follow the hole. That means the drilled hole is also not positive. If restricted to sheet metal work or similar the drill taps seem OK but I have found they are not commercially viable on long runs.

I often do long runs and believe it or not good taps last longer then drills and it's quicker to tap a hole than drill it. I often CNC drill holes and power tap with an articulated arm tapper and the tapper is always waiting for the CNC.

This is what I use, the frame is homemade and the head and collets, in the red box, are Chinese imports. Tap breakage is virtually nil now, you can belt a M4 tap into a blind hole in alloy until it stalls, then back out because each collet has it's own clutch.

Which is just a couple of belville washers keeping the two drive balls into mesh, over load these and the balls pop out.

JS.

bogstandard · « **Reply #5 on:** April 13, 2009, 07:17:19 AM »

I have admired that tapping tool ever since you have shown it John.

I will have to get in touch with my mate and see if they are throwing any out.

John

John Stevenson · « **Reply #6 on:** April 13, 2009, 07:29:12 AM »

Knowing what I know know I should have bought one years ago.
I was in the process of getting the bits to build one out of a reversible tapping head when I found that you could just get the air heads.

For a home shop I reckon a decent geared DC motor with a tapping head grafted on would be better than the one I have in that you wouldn't have to run a compressor. I think Frank Ford was looking at using one of the cheap butterfly wrench's to drive a tap adaptor but they wouldn't have a clutch.

Quite a few possibilities.

JS

Brass_Machine · « **Reply #7 on:** April 13, 2009, 09:01:17 AM »

I am tapping (50 or more) 9.5mm 6061 aluminum plates. Each plate has 12 holes to be tapped to 8 1.25 threads. Square pattern about 13mm apart.

Eric

usn ret · « **Reply #8 on:** April 13, 2009, 10:01:54 PM »

Eric, were it me drilling and tapping that many holes I would set up the mill to drill established dial settings and a vise stop for repeatability. The tapping, I would use a battery powered drill with the plates ridigidly supported to prevent tap breakage and maintain s degree of quality. Again lots of quality tapping lubrcant. For power drill tapping a 2 flute is strunger than a 4 flute tap.

Cliff

Bernd · « **Reply #9 on:** April 14, 2009, 08:55:37 AM »

At a 8-1.25" thread I don't think you need to worry about tap breakage. I'd worry more about the drill motor and tap taking my arm for a spin.

Eric, I was thinking a jig with pins located at the proper location. Drill and tap hole, turn part repeat, do four times. Remove pin drill - tap turn four times. That would work if the holes are evenly spaced all the way around.

BTW, that is an 8 threads per 1.25" is it not? or did one off us interpid that wrong.

Bernd

Brass_Machine · « **Reply #10 on:** April 14, 2009, 08:57:36 AM »

Quote from: usn ret on April 13, 2009, 10:01:54 PM

Eric, were it me drilling and tapping that many holes I would set up the mill to drill established dial settings and a vise stop for repeatability. The tapping, I would use a battery powered drill with the plates ridigidly supported to prevent tap breakage and maintain s degree of quality. Again lots of quality tapping lubrcant. For power drill tapping a 2 flute is strunger than a 4 flute tap.
Cliff

Cliff,

Could you explain in a some detail about tapping with a battery powered drill? I have one. It has a clutch. All I would need is a high speed 2 flute tap? Set the clutch or use it as a drill?

Bernd,

That is a metric tap... M8x1.25

Many thanks
Eric

Darren · « **Reply #11 on:** April 14, 2009, 10:51:16 AM »

That would have to be one serious battery drill to tap M8 threads Eric

I suppose it depends how thick the material is you are tapping?

usn ret · « **Reply #12 on:** April 14, 2009, 11:57:42 AM »

Eric, tapping 8x 1.25 {5/16-18 approx.} can be easily accomplished in 6061 alum. I have power drill tapped 1/4-20 holes in 3/8 mild steel with no problems. First drill the 12 holes per plate then clamp {vise} the plate vertically so that you can have a comfortable angle, somewhere about waist high, to hold drill steady. Protect the alum plate by covering the vise jaws with a sacrificial material, wood, copper or another piece of alum. Practice with a piece of scrap alum to get a feel for the tapping process. With 600+ holes to drill and tap get the best drill and tap you can afford. Again for freehand tapping I recommend 2 flute taps and a good tapping lubricant, Tap-magic or other lube. Use the forward reverse function on the drill for in/out.

I have probably forgotten something {CRS} , if so somebody, HELP!!!
My drill is a 18V 3/8 Dewalt and had no problems with tapping in the steel. LUBRICATION LUBRICATION LUBRICATION!!!!!!!

Cliff

Brass_Machine · « **Reply #13 on:** April 15, 2009, 08:12:56 PM »

Quote from: usn ret on April 14, 2009, 11:57:42 AM

... LUBRICATION LUBRICATION LUBRICATION!!!!!!!
...

Ciff,

You trying to tell me something?

Lol... I will get some decent lube.

Eric

usn ret · « **Reply #14 on:** April 16, 2009, 03:22:09 AM »

Eric, set the drill on the drill setting. The shank of the tap will slip if the tap binds, that is your clutch function. There is just no way to tighten the chuck tight enough to prevent slippage if the tap binds. Yes I am trying to tell you something LUBRICATION

CLIFF

Darren · « **Reply #15 on:** April 16, 2009, 03:27:28 AM »

John Bogsy,

Could you put a picture on showing your tapping stand please?
I'm using the mill to tap as it's more reliable than "my" hand tapping. Not under power but just to keep the tap square.

But, with these small taps it's not sensitive enough, too much resistance in the machine and a constant upwards pull. I could try slipping a belt off to help.
I do however have 3 pillar drills, one could be converted, the smallest. Just a bit hesitant to pull a perfectly good drill apart.

I suppose if the cause warrents then so-be-it....

bogstandard · « **Reply #16 on:** April 16, 2009, 04:48:20 AM »

Darren,

I thought there should be a load of pics in my steam engine book.

Someone has already done what you are talking about over on HMEM

http://www.homemodelenginemachinist.com/index.php?topic=3411.0

What a monstrosity. For the time and effort, he should have bought one. That is like the proverbial sledgehammer and nut. No 'feel' at all. In fact I think mine is a little on the heavy side, but as luck would have it, I have never broken a tap while using it.

When cutting fine threads, you do it with your fingertips not with a clenched white knuckle fist.

If you still can't see my stand, I will do a tiny topic with a bit of advice as well.

John

Darren · « **Reply #17 on:** April 16, 2009, 05:47:56 AM »

Ah, ok thanks,

I've only printed the appendix, need some more paper for the rest.

Thanks for the link, good inspiration as I've got another tool that's junk, that might be more suitable and lighter.
I'll have a look at it later...

usn ret · « **Reply #18 on:** April 26, 2009, 02:08:14 AM »

Eric, how are you making out with the massive tapping project????

Cliff

Brass_Machine · « **Reply #19 on:** April 26, 2009, 10:26:51 AM »

Quote from: usn ret on April 26, 2009, 02:08:14 AM

Eric, how are you making out with the massive tapping project????

Cliff

Not yet Cliff. I still have to finish the design of the parts. It probably isn't going to happen for a few months yet. I was trying to prepare myself in case I had to buy a tapping head for the mill.

Eric

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Author Topic: Tapping a lot of holes (Read 12940 times)

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