[SCzEngrgGroup]

Has any one here ever figured out a reasonable way to adjust the clutch on a reversing tapping head? Seems to me there is no reasonable/repeatable way to adjust it to provide the protection it is meant to provide.

Regards,
Ray L.

[Frogblender]

I hear you. A few years ago I bought the head Novakon sells, which I like, but I was using it just yesterday, and thinking "I don't remember the torque setting being so finicky". It is especially critical with small taps, where the window between enough torque vs. breaking the tap is small. My solution was to grab the collet with my hand to feel when it starts clutching, and take my best guess. Alas, this will not provide the repeatability you desire. Yesterday I didn't break any 6-32 taps, but I think some of my blind holes aren't quite tapped full depth either.

The torque is set by turning the torque ring. Part of the problem is not knowing exactly where I've set the torque ring. Now that you bring it up, I think I'll take a sharpie and add some numbers and indicating lines on the body of the thing (sort of like the torque setting on your cordless drill), so at least I can set the torque ring repeatably. Of course, repeatably setting the torque ring is no guarantee of repeatably setting the torque....

There are already 4 lines inscribed on the body, labelled 1,2,3,4. In fine Chinese tradition, one full rotation of the torque ring is not quite one full transition between indicating lines. Booo.

[SCzEngrgGroup]

Yeah, the markings on the body of the head are useless, and radial marks would be about as useless, since it takes multiple turns to adjust for different tap sizes. The clutch is a nice idea, but so poorly implemented, it's of no real value.

Regards,
Ray L.

[Hirudin]

MRM RCModels said in his video that he planned to basically buy a tapping head for each tap size he was planning to use. Not the most economical way to go, but ruining parts wit' broken taps doesn't save any money either. I suppose this would only make sense for three or fewer tapping heads as once you buy your fourth $200 Chinese tapping head you could have had an $800 American tapping head which doesn't need clutch adjustments.

https://www.youtube.com/watch?v=IIv8xH9razE

I wonder how that plan is working. Is the torque setting consistent enough that you can simply set it and forget it as long as you continue using the same tap?

Could you hook up a small torque wrench to the tapping head spindle and use that to adjust the torque?

[handlewanker]

Hi, I've been out of the industry for the last 10 years now, but when was active in it I used a variety of tapping heads.......mostly with just a clutch and the reversal of the machine to back out.

The only ones with a built in reversal mechanism were on the Burgomaster turret head drills I used occasionally.

The fixed tapping heads were set as the manufacturer advised by using a new tap for the start of the job and adjusting the clutch progressively tighter until it drove the tap down and slipped at the bottom......machine being reversed to back out.

The manufacturers stated that when the tapping head stalled it was time to change the tap.....blunt taps only break with increased clutch tightening.

I used to tap dozens of holes with a tap when on production tapping......in a variety of materials....same rule applies in soft or hard material as it's the torque you are setting and too much and bang goes the tap.

The tapping speed for a 19mm tap was about 250 rpm, going up to 300-400 rpm for taps down to 6mm and a thick brown tapping oil was used as lube.

All the small stuff, smaller than 6mm,were done on the Burgomaster as it had more sensitivity than the big Asquith radial drills or Kearns horizontal borers.

For tapping through holes we always without exception used spiral point or gun nosed taps that drove the chip forward and out the bottom of the hole, and for blind holes we used spiral taps that brought the chip up.

We NEVER used straight taps for machine tapping, that is the ones in sets that are reserved for hand tapping.

When a tap got blunt it had the end two threads cut off and re-pointed to be used again, as that is where all the cutting takes place....behind the first two threads the tap is just a follower and does not cut.....it will start to cut in that area if the end is blunt, but it overloads the slender shank of the tap.

In 10 years in one firm I only broke one tap through inattention to detail.

If you are doing any machine or otherwise tapping, a tap removal EDM type burner is the only tool to consider for broken tap removal.
Ian.

[MRM RCModels]

MRM RCModels said in his video that he planned to basically buy a tapping head for each tap size he was planning to use. Not the most economical way to go, but ruining parts wit' broken taps doesn't save any money either. I suppose this would only make sense for three or fewer tapping heads as once you buy your fourth $200 Chinese tapping head you could have had an $800 American tapping head which doesn't need clutch adjustments.

https://www.youtube.com/watch?v=IIv8xH9razE

I wonder how that plan is working. Is the torque setting consistent enough that you can simply set it and forget it as long as you continue using the same tap?

Could you hook up a small torque wrench to the tapping head spindle and use that to adjust the torque?

Buying 3 different heads worked out OK, but I would buy one used procunier if doing it all over again. Probably still might.

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