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

[BCRider]

I hold my taps in the lathe and drill in the regular chucks. They slip so I only start the first couple of turns. Then I loosen and pull back the chuck and use a regular tapping wrench to hold it for finishing. Not a good option for production. But good enough for home shop.

[JRouche]

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...

We are talking about home shop folks Keith. I cant afford a nice spiraled tap. Way out of my range. JR$

[Paul Alciatore]

Wow, there's an idea that has been sitting right under our noses for ... well forever. Well, at least all my life anyway. Brilliant!

And I don't say that lightly. I have devoted a lot of time thinking about just that problem: how to hold a tap without a lot of trouble or expense. And, of course all that time I had two or three or more tee style tap wrenches. Duhhh!

Looking at it suggests that you may even cut the shank back, removing the larger diameter area where the handle passes through. That would provide less stick-our when used in a mill where space under the quill is often limited.

Once again, BRILLIANT idea!

And I am going out to the shop to kick myself three times around the lathe and mill for not thinking of it myself. Video at 5.

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.

[Paul Alciatore]

I think you misunderstand. No one has really recommended spiral taps in this thread. What they are recommending are SPIRAL POINT taps which are a completely different animal. Spiral point taps have straight flutes like the common, fluted taps have. It is only the angle of the cutting edge that is sharpened at an angle that pushes the chips ahead of the tap as it advances in the hole.

And I did a quick check on prices using good, old McMaster. For a 10-32, uncoated, HSS tap the price for a standard taper, plug, or bottoming tap is about $16 EACH. The same size spiral point tap is under $8. Why? I don't know. But there you go. From at least this one source and one tap size, the spiral point taps are less expensive!

https://www.mcmaster.com/products/taps/

McMaster seems to call the spiral point taps "Chip Clearing Taps". Although their illustration, perhaps from a by-gone day, does have them labeled as "Spiral Point".

We are talking about home shop folks Keith. I cant afford a nice spiraled tap. Way out of my range. JR$

[MyrtleLake]

ER chuck with a Morse taper shank with an end tang. Loose tailstock pushed by hand. ER because tap shanks are not even, round-number diameters.

Unless it's a through hole, I start the thread as above for a solid number of turns and finish to depth with a hand tap wrench.

Drill chucks slip on ground, hardened high speed steel. Why? Because they were not meant to. Drills have a soft unhardened shank . ...it's also why solid carbide drills aren't the most secure in a normal drill chuck, FWIW. I do it anyway on occasion, but oh well. Haha

[mikey553]

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...

16N is a ball bearing chuck. I can get it from Ebay, but without a key. Can you confirm that 16N chucks are using the K4 key? I have several of them (but no chuck).

[mikey553]

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.

My biggest T-handle wrench can accept a 1/2" tap max, but it is holding a tap only by its square end, which is not ground in many cases. I have tried all 3 of my T-handle wrenches by chucking them in a lathe the best I could and installing a new, ground tap. The runout of the tap was unacceptably high in all cases. At this point I do not feel this is a viable solution.

I think the tap chucks are holding taps by a cylindrical body and only drive them by the square end.

[mikey553]

ER chuck with a Morse taper shank with an end tang. Loose tailstock pushed by hand. ER because tap shanks are not even, round-number diameters.

Unless it's a through hole, I start the thread as above for a solid number of turns and finish to depth with a hand tap wrench.

Drill chucks slip on ground, hardened high speed steel. Why? Because they were not meant to. Drills have a soft unhardened shank . ...it's also why solid carbide drills aren't the most secure in a normal drill chuck, FWIW. I do it anyway on occasion, but oh well. Haha

This may be a good solution. I have ER chucks for both lathe and mill. So do we feel that ER collet chuck has more holding power on hard steel than a drill chuck (including a ball bearing one)?

I also use a loose lathe tailstock for tapping, but my lathe is only 12" and what is OK for a 1/4-20" thread may not be good for 1/2-13" or bigger threads. Any thoughts on that?

[boslab]

When I said hold too well I was inferring they grip the shank so well there’s no slip so the tap is likely to shear, less if it’s a spiral point ( I do love the way the swarf curls out of the flute, unlike an old fashioned gash cut flute where all the crud goes down the hole)
tapping copper has always had its moments, the sudden galling up and sticking ( ping, oh crap)
stainless can have its moments too, well some grades
if I’m going to break a tap I like to look it in the eye as I snap it with an old fashioned tap wrench, I’m really good with a tee handled one, BA tap and tee handle, I’m guaranteed to break something
mark

[Tundra Twin Track]

This sliding holder for lathe work great,the 4 jaw scroll chucks were reasonably priced.

[gellfex]

My biggest T-handle wrench can accept a 1/2" tap max, but it is holding a tap only by its square end, which is not ground in many cases. I have tried all 3 of my T-handle wrenches by chucking them in a lathe the best I could and installing a new, ground tap. The runout of the tap was unacceptably high in all cases. At this point I do not feel this is a viable solution.

I think the tap chucks are holding taps by a cylindrical body and only drive them by the square end.

Runout of a tap holder is not really relevant IMO, they self center in your hole. I also would have sworn that there are tap holders with hex shanks, but I can't find it.

This sliding holder for lathe work great,the 4 jaw scroll chucks were reasonably priced.

wow, what a rig! I just let the tailstock slide.

[oxford]

I think the tap chucks are holding taps by a cylindrical body and only drive them by the square end.

That is how the Tapmatic tapping head does it. Jacobs flex collet to center and then drive the square.

[Tundra Twin Track]

Runout of a tap holder is not really relevant IMO, they self center in your hole. I also would have sworn that there are tap holders with hex shanks, but I can't find it.




wow, what a rig! I just let the tailstock slide.

Doesn’t work on my lathe tailstock is 260 lbs,#4 machine screw to 3/4” taps is the range I use this for.

[gellfex]

Doesn’t work on my lathe tailstock is 260 lbs

Good Lord! Whats the swing of that beast? 20"?

[Tundra Twin Track]

Good Lord! Whats the swing of that beast? 20"?

It’s a 18”x60”