Hi Roger, As gary has said, Normally you would use it on a capstan where the capstan would work to a stop ! Using the tailstock you have to feed the die head onto the work and then stop it at a pre determined point and there will be a pull that causes the die head to open. You should be able to make a 2MT fitting to take the die head, and depending on thread lenghth it may have to be hollow, or buy a blank 2MT arbor and adapt.  I have never used one on the S7 though I have several but I would hope that there will be someone who has ! Good luck Noel.

Hi Roger a blank arbor is in this case a 2MT shank with a solid lump at the front which you can do as you wish with, drill, thread or what ever. So looking at a couple of small die heads The shaft on the die head is 5/8″ so you would drill your arbor and put a locking screw through the side to fix the DH ! for 3″long you may have to drill down the centre of the arbor to allow the rod to pass. I think you will find blank arbors at Arc Euro Trade amonst others. Always found them very helpful and good prices/quality. Noel.

Hi Roger, I have a 1/2″ die head and use it regularly on my Super 7, I made a Morse taper adaptor to mount it int the tailstock, indeed I/we use these in industry on centre lathes and cut many hundreds of threads without any issues of the taper coming loose.

Here is a photo of mine, I did not drill through, never had the need up to now but there’s no problem in doing so within limits of course.   Many of the stub arbors on offer are too small in diameter and length, the nearest I found was here they have one 40 x 40mm better if it was larger but you could of course make your own.

On 6 February 2024 at 17:50 noel shelley Said:

…stop it at a pre determined point and there will be a pull that causes the die head to open.

It would be useful for him to read up on the specific model he has, the 12DX. It has the additional ability to be used in a slightly different manner, operating by means of an external (push) trip.

Wiseman have a digestable summary on their technical pages.

General Tech Info – Coventry Die Heads

A copy of the ‘Book of the Coventry diehead’ is available on vintagemachinery.org (under Alfred Herbert). It does not cover this newer model, but has useful information nonetheless.

I would think that for the 2-3″ of thread he says he wants, it might be necessary to disconnect the tailstock nut or to make the tailstock bed clamp slightly more sophisticated than its current ‘on’ or ‘off’.

On 6 February 2024 at 22:35 Roger King 1 Said:

Lots of really good help here, thanks all.

Thanks JohnF, I’ve ordered one of those, at £12 including postage you can’t go far wrong.  Just need to turn it down to suit and make up a sleeve to join them and I should be good to go.

Roger, not sure what you mean by “making a sleeve to join them”  you only need to mount the adaptor directly in the headstock, MT2, and bore to 1.000″ dia for a suitable depth then add grub screws.  I’m assuming your die head is the same as mine and all others I have come across where the routing shaft/spigot is 1″ dia for mounting on capstan’s the hole through is to the best of my knowledge parallel for the passage of longer threads.

I did make a couple of flats on the spigot for the grub screws – your choice but it does ensure it will not spin in the adaptor.

John

On 6 February 2024 at 18:42 Roger King 1 Said:

T

I’m wondering if a taper’s a good idea for this.  I suspect the resistance from thread cutting will result in the box spinning on the taper, but I don’t suppose there’s any alternative.

You don’t have much faith in track rod ends then? :O)

On 7 February 2024 at 13:12 Phil P Said:

This is my set up.

The original poster asked “Is there a straightforward way of mounting this device to a Super 7 tailstock?”

Would it be correct to say that your photo does not show a Super 7 tailstock?

To me, it looks like an ML7 tailstock with the quite rare Cowells rack-operated attachment. If the OP does not have these parts, what might be an alternative?

I have used a large 3/4″ diehead fastened to the cross slide.

Then another version where the work says still and the die head is rotated, still mounted on the cross slide.

Whilst that version works well, it still means faffing around removing the top slide each time, so I finally ended up with this attachment that can be fitted and removed in less than a minute.

It can be used with normal die holders and tap holders.

Hi I use my die box in the tool post  I made a block with a hole to take the shank of the box its parallel then a flat on the side to hold in tool post this then allows you to do longer threads has the bar will pass through the die box, you can even then set your gears to the right pitch and drive it from the lead screw ensuring it stays in pitch for very long threads, I could post a picture if needed.

ATB Alan