A question, from my own ignorance

[Bi11Hudson]

When tapping, it is general practice to cut half a turn to a full turn then back the tap out to break and (theoretically) clear the chips. This practice is as old as the taps themselves, it is not a new gimmick. Tap handles come in several forms, the type that brings up the question is a "T" handle that tightens down on the tap like a drill chuck. Some two jawed with notchs, some four jawed. I have several, different sizes from "tiny" to maybe a half inch. The good ones (Starrett and the like) have a step inside the tip to acommodate smaller taps. The "cheaper" ones don't have this step. My question is thus:

Prowling the tool listings on eBay, I see occasional listings for a "ratcheting" tap handle. I have used them in the past, locking the ratchet to use as a tap handle. The question has been in the back of my mind for years and just came to the front. Ratcheting a tap handle would drive the tap in the same direction all the time, just relaxing the wrist for odd positions. There would be no breaking of the chips in such use. I have restored "boogered" holes in machines and even then I would ease the tap in, just as though cutting new threads. I cannot conceive of a situation where I wouldn't use the "usual practice" of backing out every half or so turn.

Am I missing some unusual detail, or is there another use for these ratcheting tap handles. Some esoteric tool or is it just a marketing gimmick with poor practice, put on by some guy behind a desk who has never tapped a hole himself? I have built many electrical "back pans" over the years, both in thin steel and aluminum. And have tried, unsuccesfully, using a battery drill to run the tap in and back out quickly to speed up the process. Unsuccessfully would be an understatement, that is where most of my broken taps came from.

I was on oxygen for a full night last night and my mind is working overtime today. That's why this question came to the front. Any and all responses would be appreciated, even those spoofing the concept. Just something that has "bothered" me for years but I couldn't properly phrase the question.

Bi11 Hudson​

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[jwmelvin]

I imagined they are for tight quarters. I also imagined they must have a reversing feature, to get the tap out. So it should be possible to periodically reverse and break the chips. But I also imagine because of the extra work required, they make one less likely to break the chip as often. I don’t have one and don’t really know what I’m talking about.

 

[jbobb1]

I bought a ratchet tap handle for a situation as mentioned above. I could only turn the standard handle a little over a quarter turn. It does has a reversing switch like you find on the ratcheting screwdrivers.
As far as how often I will back out a tap to break chips really depends on tap size and materials.

 

[benmychree]

Yes, the ratcheting tap handle that I have has a reversing feature and also a locking feature. In my experience it is possible, with a sharp tap, to rotate the tap without reversing to break the chip, even when using a standard plug tap, and especially if using a spiral pointed tap or a tap with spiral flutes, one drives the chip ahead of the tap, the other brings the chip up the flute, these are designed primarily for machine tapping. The spiral pointed taps are not so good in the smaller sizes with only two flutes for hand tapping, as they are easily broken with side pressure. One of the most important details in tapping is the use of a cutting fluid, the best, in my opinion is TapMagic.

 

[Aukai]

I hope your need for supplemental O2 is not serious, or long term. I have wondered why a power tapping head can go all the way through a hole, and hand tapping, reversing is a must you can physically feel. I have used the ratchet tapping head flipping the switch as I go.
^^^I see my answers above....

 

[davidpbest]

A ratcheting tap handle is useful in constricted situation where you don't have freedom of movement to rotate the handle 360-degrees. It serves the same purpose as a ratchet handle used with hex-sockets. If you want self-clearing taps, consider a different style tap like a spriral-point tap that drives the chips down and out the bottom of the hole. See attached.

 

[brino]

Hi Bill,

I get your point.

I have used one.
Depending on thread depth, tap type and material, it can be convenient to rotate a full turn forward and then a quarter turn back to break chips.
As long as the ratchet reversing mechanism is not too cumbersome, I think it can save time....but I've never timed a side-by-side comparison.

-brino

 

[Aukai]

Thank you for posting that David, probably not the first time I downloaded it.
I wonder where it would fit as a sticky.....

 

[benmychree]

Power tapping is possible because taps are made for power tapping, as I said earlier, the spiral point type and the spiral flute type.

 

[Bi11Hudson]

Aukai: My old house (1887?) is pretty airtight, especially for the deep south. Wife is from Maine, where it really matters. She has "updated" a number of leaks. I don't use the O2 much in the summer with open windows, but in cooler (<70F) weather I do. I finagled one from the VA for snoring. I don't much, but all those years around hot metal have taken their toll on my lungs. Add to that I am a (heavy) smoker, high Mullein content, and the air gets heavy when the house is closed up.

Thank you for posting that David, probably not the first time I downloaded it.
I wonder where it would fit as a sticky.....

I also downloaded it. Very good information. Most of the details I already know, but the article is well written and very well organized.

Brino: I haven't done a "head to head" test, but the few times I have used them in the field, clicking back and forth put a lot of side strain on the tap. That's why I just lock the ratchet. I usually work with smaller taps, 1/4-20 and smaller, so that is a real issue to me. It may be different with big stuff but thankfully I have never faced that.

For all others, I am aware of the tight quarters problem. Have had to deal with it for many years. I tried the ratcheting handle, unsuccessfully, and have always finagled an extension of some sort since. I can't count the number of times I have used a 1/4 extension backwards with wedges to hold the tap. I usually associate spiral flute and spiral point taps with machine tapping, not hand tapping in the field.

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