Tapping head?

[cnczoner]

I've been casually looking into tapping heads and wondering if they really work as simple and trouble-free as touted. I will generally need 4-40, 6-32 and 8-32, and many of those will be blind holes. Occassionally 10-32 and 1/4-20. I think a tapmatic 30x will handle this.

But is it really as simple as portrayed? Manually, I usually can't tap all the way thru aluminum in one pass, even if the hole is drilled all the way thru, without breaking the tap. So I generally tap a few turns, back out, wipe the chips off the channels in the tap, then continue tapping. An example is 8-32, 0.375" deep where I find that I need to clean the tap about 3 times.

Also, with my non-spindle-controlled milled, can I tap blind holes with one of these heads? I've not seen any feature that will stop the tapping head after a preset depth, etc.

Cheers,
-Neil.

[Geof]

You are maybe correct being dubious about using tapping heads with 4-40 or 6-32 in aluminum alloys. We do tap 8-32 through about 3/8" in aluminum successfully on a regular basis but 6-32 is not easy unless you drill the tapping hole for only a 65% thread and go with longer thread engagement. you do have to use a good tapping lubricant of course. 10-32 or 1/4-20 is quite simple.

Regarding tapping blind holes it is difficult to have really blind holes where the tap has to stop within a couple of turns from the bottom. Some of the tapping head have provision for a stop that contacts the workpiece so the drive will disengage at a set depth but there is some 'spring' in the mechanism so it is best to have some leeway, and of course you have to use a spiral flute tap.

[widgitmaster]

Originally Posted by cnczoner I've been casually looking into tapping heads and wondering if they really work as simple and trouble-free as touted. I will generally need 4-40, 6-32 and 8-32, and many of those will be blind holes. Occassionally 10-32 and 1/4-20. I think a tapmatic 30x will handle this. But is it really as simple as portrayed? Manually, I usually can't tap all the way thru aluminum in one pass, even if the hole is drilled all the way thru, without breaking the tap. So I generally tap a few turns, back out, wipe the chips off the channels in the tap, then continue tapping. An example is 8-32, 0.375" deep where I find that I need to clean the tap about 3 times. Also, with my non-spindle-controlled milled, can I tap blind holes with one of these heads? I've not seen any feature that will stop the tapping head after a preset depth, etc. Cheers, -Neil.

I use a 30x TapMatic all the time, they are excellent tapping heads!

They have a torque adjust clutch, which can be gentle enough of an 0-80 or strong enough for a 1/14-20 tap!

The depth is controlled at the quill, and the tap will disengage when it reaches depth. When the quill is retracted, the tap reverses direction and it screws out! and you are now ready for another hole!

Tapping heads require either a spiral point tap or a roll form tap, the old 4-flute hand plug taps will not work at all.


Widgit

[cnczoner]

Hmmm... encouraging. I just need the correct taps/oils etc. So far I've been using home-depot hand taps with 10W-30 motor oil :-) Been meaning to try hope-depot's dark pipe threading oil.

My applications would be 1/4" or 3/8" alum plate that would need to have some mounting screws on the back for PCB's or securing the plate itself, without any screws or holes visible on the front. From 0.25", if we leave 0.050 inch of material, that leaves 0.20" to be drilled/tapped. At 32tpi, that's about 6 threads . Since a bottoming tap would leave a couple chamfered (unusable) threads at the end, that leaves about 4 usable threads which is fine. So it would work in theory, if the tapping head has good enough depth control for this.

IIRC, I'm pretty sure tapmatic has instructions on their website -- I should really read it before purchasing anything shouldn't I?

Cheers,
-Neil.

[Geof]

Regular motor oil is pretty much useless for tapping, or any metal cutting on most metals and totally useless on aluminum. Strangely enough Dexron ATF works very well. Kerosene also works well but smells.

But the best thing is get hold of some proper tapping fluid for whatever material you are working with.

[DareBee]

Definitely get some Tap Magic EP Extra (designed for aluminum). Proper cutting fluid makes a world of difference. Dark threading oil is not good for your application.
Your other big issue is the taps you are using.
For blind holes get spiral flute MACHINE taps.

You will be shocked at the difference these 2 changes will make.

[neilw20]

Tap Magic is really good.
We have no problem in Australia because metric taps are much finer pitch that your 6-32, 4-40, 8-32 etc. (LOL)