Tap Chuck - How do you use this?

[YYCHM]

This came with my lathe....



I didn't think it had anything to do with the lathe at all until I had a closer look at it.

It's labeled 1/2 M Tap Chuck.

It has a 2MT taper, so, it fit's in my tail stock. The center bore is 3/8".

How would I go about using it?

Craig

 

[Brent H]

It will hold a 3/8” diameter straight drill shaft or tap shaft or - as I use it - a centre drill bit

 

[YYCHM]

It will hold a 3/8” diameter straight drill shaft or tap shaft or - as I use it - a centre drill bit

Ok, so there is no real magic about it being labeled a tap chuck then? Basically a 3/8" MT2 arbor/collet. Do you dare use a manual tap in such a thing?

 

[Brent H]

It would fit into a Morse taper tapping head for say a mill or drill press and keep your tap centred - it probably has a square broached pocket at the back to further secure a tap. More for speed of changing out the tooling.

 

[PeterT]

Shine a flashlight down & see if it has a square hole at the end of the bore. I'd be surprised but ya never know. If it doesn't, than its basically a cylindrical shank holder.

Also check if your lathe tailstock actually has a receptacle socket for the anti-rotation tang. Often times they don't. Which means you are relying on the fit of the MT taper in the quill barrel. Not that it wont work but wouldn't really be my go-to tool. Also confirm that you can actually eject the arbor in your TS beforehand. There are some oddball lengths & whatnot out there.

 

[YYCHM]

It has a square pocket at the back of the bore.

A 3/8" drill bit only seats 1/2" deep in it, so not sure I would trust it for that kind of duty. My tail stock quill doesn't engage an anti-rotation tang. It will accept it but not engage it.

Numbered center drills don't come in a 3/8" body dia. so can't use if for that.

I guess it's not much use to me then

 

[francist]

You can still get them new but not particularly cheap. Collis is a popular brand if not the most predominant (I think Skully-Jones made them too). They start around $45 for the smaller ones.

 

[YYCHM]

Holy Smokes!!!! Pricey stuff

 

[PeterT]

That's interesting. I've heard of that style of collet but never really had an appreciation for their implementation. So the square broach prevents rotation of tap to collet. But if you don't have tang receptacle then the possible slip will be on the O.D. MT tapered arbor surface the mating quill ID. I'm not sure, maybe taps come (or came in) nominal shank sizes, so maybe 3/8 shank covered several taps on either side, then set down to 1/4 for smaller or step up to 1/2 for larger range?. That would make it more universal & maybe less collets to own. I know with the tap holders I made the shanks tend to vary a bit by manufacturer & metric are different again.

I find the whole tapping on a lathe exercise kind of variable, people do it different ways. I'm a bit leary of driving in under power because you have no feel for overload unless the tap spins in whatever is holding it, or worse yet breaks. For small stuff I just lightly push the tailstock into the part, either rotating the chuck real low rpm or by hand. If its a higher load I just initialize threading so engagement is straight & attach a tap handle so I can back it out & feel what's going on. But I am certainly no pro so this might be making more work than necessary. I often wondered why there wasn't a clutch type tap holder similar to what you see in a (mill/drillpress) tapping head, except for tailstocks which is now the stationary part. Maybe they exist?

 

[francist]

I’m thinking that would be a Geometric Tapping Head, aka chaser. Adjustable clutch and reversing lever. Adam Booth has one or two videos where he uses his.

Edit — hmm, just realizing I’ve only ever seen the Geometric used for external threading. Don’t know if it does or would work for internal tapping application. -f