Drill Chuck as Tap Holder

[Antman]

Hi Guys,
I've been using a commercial collet type tap holder in a sliding arrangement for tapping from the tailstock and in the mill, but have not been too impressed by its holding power and the range of sizes it can hold. Also the type of tap holder with the 2 V-blocks, but these cannot be easily incorporated in a sliding holder. So I was thinking of a small 10mm drill chuck, available quite cheap. All it needs is a threaded arbour to make a dedicated tap holder. Good idea or not?
Ant

 

[Herbiev]

That is a brilliant idea. If they still had karma points I'd send you a couple.

 

[metal_magician]

If it can hold a tap you can tap with it. Just bump tap with the machine. Meaning, have machine on slowest speed and toggle the forward switch on and off to make the rpm even slower! And if you are using super tiny taps like 0-80 or 00-90 use it to just start the tap in the hole, that way you know when you pull the part out and hand tap the hole that the tap is running perp to the surface and parallel to the hole. Good luck. Ps...lots and lots of tap oil....what ever works best for you!

 

[Antman]

You really think so, Herbie? Normal tapholders suck. Whoa there MM I hand crank my lathe, when I get a lathe with brakes and clutches, maybe.
Ant

 

[MachineTom]

I find that most taps spin in the chuck for 3/8 and larger, get a set of Tap sockets and a hex to square adapter, both 1/4 and 3/8 square. cheap and bullet proof.

 

[Don1966]

Try this it works fine http://littlemachineshop.com/products/product_view.php?ProductID=2504&category=

Don

 

[rkepler]

A tap is like an endmill in that the shank is hard and not soft as a drill shank is, and drill chucks are not really made to grip hard shanks (modulo the occasional chuck with diamond coated jaws made for carbide drills). A drill chuck may sometimes work but usually won't hold a tap in hard work without really cranking on the chuck, often to the point of damaging the chuck.

But for small taps in light work you can usually get away with it.

 

[Noitoen]

Just file, with a diamond file, 3 very shallow flats along the shank of the tap and it won't spin any more on the chuck. It works for me (I use a Dremel with a little grinding wheel)

 

[mcostello]

I have seen a small Jacobs drill chuck with 4 jaws at a yard sale that someone just had bought. Never seen another, might look when circumstances arise.

 

[syrtismajor]

I often use a three-jaw drill chuck for holding taps but this is only for ones less that 10mm in diameter. It is always handy when you're making something in a lathe and you want to tap the hole you've just drilled. It saves changing over any tools on the lathe!
I wouldn't however over tighten the chuck to reduce the chance of damaging the tap or the chuck. I also power off the lathe (including the emergency stop) and turn the piece by hand, this gives an excellent feel to how much torque you're placing on the tap, always good when dealing with small ones.... just remember to ensure that the tailstock is free to move!

 

[Antman]

Thanks guys for you answers. I had heard that holding an endmill in a drillchuck was a no-no but didn't know the reason, same as taps. However I will only use it for hand powered tapping in sizes up to M8, so I'll give it a bash. If it don't work I'm sure I can use the chuck somewhere else, anyway it is cheap at the local tractor spares shop, about 6 cans of Coke.

 

[rkepler]

It's probably bad form to mention that when I'm in a hurry and tapping through holes in sheet I'll often chuck up a spiral point tap and run it through under power - usually at a low speed (10hz on the VFD and so spindle about 300 rpm) and using the reverse at the end to back the tap out. I know of folks without VFD but with 3 phase "plug reversing" the spindle to stop and reverse out, it's never really a problem if you're not going fast.

If I have a lot of holes I'll break out a tapping head and go through the effort of setting it up. But I won't do that if it's a special (like 1/4-40) or weak tap (like a 6-32) as it can be hard on taps. But when you have a lot of holes (I recently did 600+ 4-40 holes) there's nothing better.

But usually I have only a couple of holes and so I use the tapholder with the stub on the back in a quick change endmill holder. Only downside there is that it usually wants more headspace than I needed for the drilling operation.

On the lathe I don't do anything special, just manual tapping. I use the same tapholder with stub but use the stub in a 1/2" MT2 endmill holder.

 

[keskeesha]

What Rkepler said.
kes