Power tapping - what do you use to hold the tap?

[mikey553]

Believe it or not, but I still tap all my threads by hand. I would start them straight by a lathe or mill and then finish by hand. This is getting old for me. I do not have any tapping heads or chucks. The 1/2" keyed drill chuck on my lathe cannot hold a tap - it is slipping. Perhaps I need a better chuck. I have a 3/4" keyed one, but did not try it yet. Would it be any better? Can keyless chucks hold a tap or it is just asking for trouble?

I can see the expensive tapping chucks for sale, where each tap size requires a special collet. I do not tap so many holes to justify that. Is there a cheap solution for my problem? What do you do in your shops?

[JRouche]

I think my tapper uses jacobs rubber flex collets. They hold well but are a lil pricey. JR

[boslab]

A keyless might help but beware on small taps, can hold it too well, no slip at all I discovered, so keep the worn keyed chuck for small and use the keyless fit more substantial taps,
mark

[Jim Stewart]

I use my Jacobs ball bearing chucks in both the mill and the lathe.
And I don't tighten them much - I want a tap to slip rather than break.

BUT: I use spiral point taps when machine tapping. If you're using regular taps you're going to have problems...

-js

[mikey553]

BUT: I use spiral point taps when machine tapping. If you're using regular taps you're going to have problems...

-js

Can you elaborate? I have some spiral point taps (not spiral flute). Why would they perform better?

[mikey553]

I use my Jacobs ball bearing chucks in both the mill and the lathe.
And I don't tighten them much - I want a tap to slip rather than break.

-js

My chucks are regular, not ball bearing ones. That probably makes a big difference.

[mikey553]

A keyless might help but beware on small taps, can hold it too well, no slip at all I discovered, so keep the worn keyed chuck for small and use the keyless fit more substantial taps,
mark

I have a couple of good keyless chucks for my mill, but don't want to damage them by holding taps. Should I get a couple of cheap ones just for tapping, one for a lathe and one for a mill?
What do you mean by holding the tap too well? You cannot open the chuck after tapping?

[Mcgyver]

Use a regular chuck, and not my best one. get it really tight, tighten on all holes, and have at it. I'm not doing much large stuff, this works on smaller stuff

[Jim Stewart]

Can you elaborate? I have some spiral point taps (not spiral flute). Why would they perform better?

Regular taps - intended for hand tapping - need to be backed-off to clear chips every half-turn or so. Not suitable for power tapping.

Spiral point taps (also called gun taps) shoot the chips out ahead of the cut and need not be backed-off to clear them. But obviously they can't be used in a blind hole unless there's enough space ahead of the threads to hold the chips.

Spiral flute taps clear the chips backwards, away from the threaded area, so can be used in blind holes. But they're sorta fragile.

So I always use spiral point taps in a through hole, even when hand tapping. Nice not to have to clear chips.

-js

[oxford]

I use my keyless chuck in the mill.

In a hand drill with a slipping chuck I will use a tap socket and a hex adapter. (You can also get decent results gripping on the square drive with a 3 jaw chuck if need be)

Regular Jacobs chuck in the lathe.

Already mentioned, spiral point taps for through holes (or adequate hole depth to accommodate for the chip). Spiral flute for blind holes. I’ll use the quill stop on the mill for a depth gauge. Run it down until it just reaches the stop and then reverse.

[Jim Stewart]

My chucks are regular, not ball bearing ones. That probably makes a big difference.

Try those chucks with spiral point taps. I doubt the ball-bearing chuck matters because I don't tighten it much at all. Less than for a drill by half, maybe.

-js

[oxford]

For reference, I crank my chucks down. Small taps might not matter as much but it takes quite a bit to drive a 1/2-13 in.

[Bob Engelhardt]

T-handle tap wrench: remove the bar and hold it in the drill chuck. The tap is secure & the wrench is soft enough for the chuck to grab. Cheap.

[55fairlane]

Lathe.....I have Morse taper sleeves just ment for taps (and use spiral cut when you can)

Mill/drill I have a tapmatic tapping head.....

[LKeithR]

...I use spiral point taps when machine tapping...

Spiral point taps are definitely the way to go. They do need to be good, brand name taps and they
also need to be sharp, not dull. The other thing is to make sure your hole size is correct--in harder
materials like 4140 steel or stainless you can sometimes even get away with a hole that is slightly
oversize. As long as I use good taps I can power tap everything up to at least 3/4" using a good
Jacobs 16N chuck...