What is this fourth (threaded) hole in the die stock holder ?

The die stock holder I ordered arrived today and there is a fourth hole which is threaded just to the front right in the photo. What is this hole for ?

**LINK**

I have this hole on some of mine too - never used it, only the top three but I thinks it's for dies that are not split - ie don't have a gap so they are held in two places?

If you have a screw in the centre in the split this stops the die rotating but when I was taught to use one I was told you could slacken this centre screw and tighten the outer screws to close the die up a bit to cut a deeper thread?

I never bother, just do all three up, never very tight and nothing has slipped so far (the force it trying to rotate the die in the holder and the screw in the split stops this?)

If I am wrong I am sure someone will correct me

Chris

Was told that the correct complement of holes is 5. All my decent ones are equipped with the three you normally use with a split die on one side of the handles and two on t'other side at left and right in positions corresponding to the fourth one on the die stock Brian bought. Allegedly this is so that hex die nuts can be held without damage using 4 screws with the fifth, split position, screw backed off and out of the way.

Apparently good quality hex die nuts should have suitable recesses in the sides for the screw points. Not that I've ever seen any so fitted. Come to think of it I don't think I've ever seen anything that might be called a good quality hex die nut. Always assuming there are such things. However several of my dies have recesses for the extra screws. Makes sense with the big pipe dies where some extra drive points are probably useful given that the stock is approaching 2 ft across so the long handles give plenty of leverage. But 5 driving points on a small die seems excessive. Think my 10 BA one has 5 recesses.

Clive

Hi Chris, the split die should be adjusted so that it runs freely down a standard bolt, this will then cut slightly oversize.It will also make cutting the thread slightly easier. It should then be adjusted to take small finishing cuts which will result in perfectly sized threads with an excellent finish. Do not open the die too much if the die stock is too large, or the button die O.D. is undersized as there is a chance that you could break the die. The two screws to the side of the split should be nipped up to prevent the die from opening while in use (giving an uneven thread or breaking the die). By tightening these against the central screw, fine size adjustment can be made.

Hope this is of interest, Roy.

Edited By Roy M on 04/05/2014 00:02:44

Edited By Roy M on 04/05/2014 00:03:49

And while we are on the topic, why do the makers never leave enough metal thickness for the grub-screws to engage properly? The average tap has a small chamfer in the slot, and this means that most of the point of the screw is up the hole, leaving too few threads enaged.

And is there an advantage in using grub screws rather than hex heads (or socket heads) ?

Cheers, Tim

maybe because grub screws come in cone-pointed variaties don't think set-screws do.

I thought ''grub screws'' and ''set screws'' were different terms for the same thing ?

A set screw has thread all the way down from under the head as opposed to a bolt that only has threads close to the end with a plain portion between the underside of the head and this threaded part.

A grub screw has thread all along and is of constant O/D the head style is usually either internal hex. or slotted. The "point" can have various styles to suit the actual application.

Hope this helps.

Eric