Tailstock tapping chuck

Been there,done that ,never found those things to be of any use. Same for die holders.

I had the same problem. A while back Michael Horner posted a simple idea for tapping on the lathe, see:

http://mikesworkshop.weebly.com/tailstock-tap-holder.html

This works very well.

I also made this chuck:

http://mikesworkshop.weebly.com/improved-chuck-for-taps.html

for use on my pillar tool. This was based on an idea for a tap wrench published in ME by W E Briley in 1964. This is a more complex chuck but it also works very well and can handle a wide range of tap sizes.

Bob

Proper tapping attachments as intended for use on drills and milling machine have a device to hold the square on the tap to provide drive. The hand tightened chuck is just for alignment purposes.

My Pollard tappers have chucks remarkably similar to those supplied with old style, inexpensive, hand cranked drills backed up by a floating square holder. The square holder is basically a pair of collars which draw together by means of an internal screw. The collar diameter is made large enough to grip perhaps half the square depth when its pushed hard up against the central screw.

If your chuck is hollow it ought to be possible to come up with something along similar lines. Given the limited number of sizes of square required it might be easier to just make inserts with a suitable cut out. Perhaps a pair od D shaped rods with matching slots milled into each side sliding into a cross drilling might work. Easy to amok but no obvious way of arranging for things to tighten up so tap driver engagement will be slack.

You do need to arrange some form of self alignment floating.

Clive.

PS :- Interesting links from Michael.  Not sure about the first one as the usual pin chuck type wrenches supplied with sets aren't very good.  The four sided square gripper is cunning and obviously effective but may take a bit of making.  Given that the commercial pollard tapping chucks simply grip two sides of the square between a pair of collars it may be over sophisticated for the job.

Edited By Clive Foster on 31/08/2018 13:08:19

Edited By Clive Foster on 31/08/2018 13:08:40

Edited By Clive Foster on 31/08/2018 13:09:24

Coventry die head ?

Perhaps something on the basic idea used in taps of two v-shapes but join them with a rod theaded left and right hand to adjust and on the usual sliding rod in tailstock.

I also made one of the basic ones a while back usng a cheapo small chuck from china. It's good to about M5 before it lets go.

Ronan Coventry die head for a tap ??

Roy

If you use a keyless chuck it will self tighten as the tap starts to slip. When you reverse though it will let go.

Russell

If you have the same set up for the die holder then simply make a round holder that fits the existing die holder but drill and tap it with 4 grub screws these lock onto the square end of the tap holding it in place and then just use as normal,

I will see if I can upload a photo of mine tonight for you

trevor

Just to explain a little further, if you make a round tapping guide block that fits the die holder and extend it in length

its possible to secure it in the die holder by the 3 grub screws on the existing die holder and on the extension have a further 4 grub screws that hold /locate on the square end of the tap

I machined a set of guide blocks to suit the different diameters of the taps that all fit the 1 die holder

it makes tapping work held in the lathe very easy and I can use the lathe forward and reverse to do all of the work

cheers

"If you use a keyless chuck it will self tighten as the tap starts to slip. When you reverse though it will let go." Not so hot for Left Handed threads.

Bob

I have created an album showing how I overcame the problem although it was not my idea but I can’t seem to find out who on this forum did

Either way it works well for me

Regards Trevor

Edited By Trevorh on 31/08/2018 18:21:49

Hi there

Steve Jordan has a good system using an ER collet chuck. Yotube again

Regards Adam

I just use a regular Jacobs chuck to hold the tap. I leave the tailstock unclamped so it can float. I usually tap under power.

I have Tailstock Die Holder, (takes various sizes of Die). It slides on an arbor in the Tailstock taper, (3MT in this case).

I made up an ER25 collet holder to slide on the arbor. Does not need to be too close a fit, (No more than the Die Holder body) so that the Tap can self align. The Clamp nut needs to be quite tight to prevent the Tap from slipping, in larger sizes, (> 1/4" /6mm). But once started , with the Tap square to the work, tapping can be completed using a tap wrench. Like the Die Holder, it has a short arm which can rest against the four way tool post, to resist torque.

For smaller and finer threads, it takes away the task of the tap trying to pull the Tailstock along the bed, with the risk of stripped threads!

Howard

Edited By Howard Lewis on 31/08/2018 20:08:17

God yes, don't know what i was thinking.

I don't bother with a special tap holder in the manual lathe. I just use the drill chuck. But I don't do much tapping in the manual lathe, more usually screwcutting. When I do the drill chuck is done up by hand and the spindle turned by hand until the tap slips. That's usually a couple of turns which is enough to keep the tap straight when finishing by hand. I've recently bought a sliding tailstock dieholder for a specific job, but again it's not something I'll be using a lot.

Tapping on the manual mill is done with reversing tapping heads, which one depends on the size of tap. As Clive says they've got a square drive above the rubberflex collets. On the CNC mill I use a tension/compression head with ER collets.

Most tapping on a lathe is done on the repetition lathe where I've got tapping heads driven by dog and freewheel clutches, although they rely on being able to instantly reverse the motor. Interestingly the tapping heads do not have a square drive, just a set screw onto the shank of the tap. The biggest tap I've used so far in the head is 5/16" BSF, which was fine tapping at 500rpm in steel.

Andrew

Not a Coventry but a Landis and a bit on the large size for the OP (I'm sure we had slightly smaller ones at RR though)

**LINK**