taper vs plug taps

I've noticed that most of my taps are more like a plug tap than a
taper tap, expecially in small sizes.
So I wonder how many use plug taps instead of taper taps.
Wes
Reply to
clutch
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Plug taps are generally used when tapping by hand. A taper tap has slight advantage in through holes in a production environment, but not much of an advantage on short run or repair work.
Reply to
Roger Shoaf
I use spiral-point plug taps exclusively. I think hand-taps are a *complete* waste of time, even if taping by hand. Spiral-point taps do not require any reversing until the hole is completely threaded. I don't see any drawbacks other than taper hand taps are perhaps easier to square by hand than plug taps.
Regards,
Robin
Reply to
Robin S.
Simple.
If it is pre-tapped - use a plug. If there is a bottom hole issue - plug. If it is a new tap - use a taper and then a plug if needed. Tapers start nice.
Simple as that.
Then, there are different taps that have ? H(number) ? and that indicates the effective depth of cut or % of cut.....
More taps..
Martin Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.
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snipped-for-privacy@lycos.com wrote:
Reply to
Martin H. Eastburn
I tried using plug taps without using taper taps first, it does not work well.
i
Reply to
Ignoramus30656
Want to give that some more thought, Roger?
Plug taps are generally used when power tapping, where starting the thread isn't an issue. There is almost no need nor reason to use a taper tap in a production environment. Fact is, they're pretty much relegated to hand taps.
Through holes are generally tapped with spiral pointed gun taps, and anything less is a stupid idea. You can tap a hole and be back out of it in something like 5 seconds by using that kind of tap.
There's lots more to this issue than how simple it appears, depending on many variables.
Harold
Reply to
Harold and Susan Vordos
Close-----but no cigar. If there's a bottom issue, use a bottom tap. That's what they're for. Almost no lead, and difficult to use, but effective for getting that last couple turns. It's nearly impossible to start a hole with one.
Only by hand--------and never, ever, power tap with hand taps unless the material in question is very thin. It's an instant recipe for a broken tap. There is no need for taper taps when power tapping.
No-----it indicates the theoretical pitch diameter of the tapped hole. Drill size dictates the depth of cut.
Harold
Reply to
Harold and Susan Vordos
Possible terminology issue:-
Only in the US a second tap is a plug tap and a plug tap is a bottoming tap.
Mark Rand (not from the US :-) RTFM
Reply to
Mark Rand
snip---
Interesting possibility! :-)
Harold
Reply to
Harold and Susan Vordos
I almost always use spiral ground bottoming taps intended for machine-use. And always use them by hand. The tap sets with three taps are collecting dust.
Nick
Reply to
Nick Mueller
What is a gun tap ?
Reply to
mrbill2
Why did write that I in "to front backwards cherman grammar"???
Must be this cold I've got. It's addled my brain even more.
Mark Rand RTFM
Reply to
Mark Rand
[snip]
Most of my tapping is performed using a Bridgeport or lathe. (sometimes an electric drill in control panels).
The most crooked hole I have ever made was with a 5/8 NC taper tap by hand. I got it a bit crooked and it kept going and going off axis.
My curiosity was peaked by thinking, all these taps cut one thread per revolution. To some degree, the torque required should be the same unless the depth of cut is a major factor since Bottom > plug > taper.
Elucidation on the subject will be well received.
Wes
Reply to
clutch
I won't claim any expertise here, but I think that is a bad assumption.
Each of the taps - unless it is a tap whose taper length exceeds the thickness of the material - will remove one full thread's worth of material with every revolution. The torque necessary to remove that material depends on the amount of material removed, but it also depends on the width of the cut. A bottoming tap without any taper might remove all of the material with one tooth. A taper tap with the taper ground for six threads would cut over at least six teeth, or six times the number of flutes. I'd have to think about that one a bit - I suppose the accuracy of the tap would determine how many teeth actually do any cutting.
I think a long taper tap might be like a taper reamer. You take off very little material with each turn of a taper reamer but, because of the long length of cut, it takes a lot of torque to turn.
John Martin
Reply to
John Martin
The problem with bottoming taps is the point load, or load per tooth. It's dead easy to break a tooth in tough materials---whereas with plug or taper taps, the chip load per tooth is much lighter. Load on the shank may or may not be the same. As a result, those of us with experience tend to avoid bottoming taps, but instead use a modified plug tap that has been somewhat shortened, and go in a tapped hole to remove just the small amount needed to establish full depth. The shortened tap usually allows for a couple more turns. Just like a bottoming tap, they don't start well, but are good for cleaning out the tapered portion of an existing tapped hole.
It's usually desirable, if you're trying for a full thread depth, to use taps progressively (when hand tapping), so each tap removes a little more of the material, yielding less for the bottom tap to remove. That lowers the point load.
You likely realize that there are variables, and what works one time may not another. Doesn't hurt to have a background in tapping, so you have experience to call on to address questions that may arise.
Harold
Reply to
Harold and Susan Vordos
Chuckle! Likely so. Still, I understood what you meant.
There are several phrases that differ from one side of the pond to the other. I always chuckle when I see the word "swarf" used for all chips. Swarf, here in the States, is connotation for the fines generated by something like a grinding wheel. Ever notice they offer chip removal systems with production machines, not swarf removal systems? :-)
Get well, Mark!
Harold
Reply to
Harold and Susan Vordos
Gun taps are two or three straight fluted taps with a spiral pointed end. By design, they make poor hand taps, but work well when power driven. The design of the spiral point drives the chips ahead of the tap, so you get a set of chips that are intertwined from the opposite end of the hole, usually an unbroken rope, so to speak. Such a tap will work for blind hole tapping, but the hole must be deep enough to allow the chip to accumulate, and can be difficult to remove unless you can break it up after tapping.
Harold
Reply to
Harold and Susan Vordos
They are for through holes, certainly not for blind holes.
Nick
Reply to
Nick Mueller
Depends on circumstances, eh? I've used the hell out of them for blind holes with outstanding success. You must have chip clearance, otherwise they work fine.
Harold
Reply to
Harold and Susan Vordos
If having to drill a deeper hole and poking the jammed chips out of the hole is a success. :-)
Why not use a blind hole tap? They also work in through holes without jamming.
Nick
Reply to
Nick Mueller

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