Bent thread

+1 for that!

The central screw for opening the die-split is often quite unsuitable - a dog-point is generally useless unless the split has an especially wide vee. Sometimes I've made a new one from a capscrew with a little tommy-bar through its head and a turned 40 - odd degree incl. vee point. This'll open up the die till it's hard against the holder's I/D, but it'll also put a lot of stress on the tapped thread in the mazak holder - remains to be seen how long that'll last.

Cheap(-ish) sets of very adequate metric taps and dies in some stuff they call 'tungsten steel' are available from Machine Mart. They work well enough for everything I routinely do and I only need to buy a new set every couple of decades, and that's usually cos of broken taps in difficult materials rather than worn-out dies.

Personally I no longer buy from Tracy Tools. I got so frustrated with the last set of taps and die that I widlarised them:

Andrew

The set I meant from Machine Mart is CHT303. The diestock centre screw has the usual fault, and for blind or shouldered holes you may want to grind the points off some of the taps - carefully, they obviously don't dare to call their tungsten steel 'HSS', so you don't wanna get it too hot. But they've served me well for 90-odd% of what I've done this millenium...

Mine is the same. And the M10x1.5 has done a lot of work, both in the lathe and vice, in brass, steel and aluminium.

The central screw on most of the newly bought, economically-priced three-screw die holders I've got were originally cone points rather than dog points. Sadly, these screws are generally too soft to do the work of opening the split of a split die; they typically get mulched after a few uses. I replaced them early on with Grade 14.9 cone point socket set screws. These are up to the job.

By way of contrast, the secondhand Dormer and Toga die holders I've got had much tougher cone point screws when I acquired them. These didn't need upgrading.

So I do sympathize with this aspect of Martin's problems.

Todays update, I have bought a new 1" Volkel die from Rotagrip and a new, reputedly drop forged steel, Volkel die stock from another supplier. This is possibly over the top, it certainly wasn't cheap, for what I'm trying to achieve, but I can't see any point in persevering with probably damaged die and stock. It was approaching the point where the workshop wall was going to get dented. I'll see what happens when the new bits arrive, I now have a far better understanding than I did three days ago, thanks all.

Regards

Martin

Martin,

The cost soon be forgotten on quality items.

Looking forward to a further update when the tools arrive.

Jim

This all ground to a halt after my last post. New dies were ordered from Rotagrip and despatched which was the last anyone has seen them, lost in a Royal Mail office somewhere. Obviously new ones weren't going to be sent until the claim period had expired and this coincided with the coldest spell since I've lived in this house. I could warm the attic workshop with warm air from below and turning the radiator upto full, the fuel bill didn't want to be thought about. As it was the replacement dies arrived on Saturday, meanwhile I had ordered various new threading equipment and consumables, I think I may have had a blind spot here as nothing of threading bits was really up to scratch, a decent set of BA taps and dies is due to be bought in the new year.

Having collected all the bits together a new stud blank was turned and duly offered up to the new die and with a prayer to Mr Whitworth, a thread was cut which joy of joys was perfect first time. Encouraged I turned it round and did the other end with the same success. I was so taken aback at the apparent ease that I did wonder why the last attempt was so abysmal, partly my technique which has undoubtedly benefited from the advice here but also I think the die especially was just plain faulty. Certainly Herr Volkel's products seem to work as you would expect and whilst perhaps more expensive than alternatives worth it for the lack of drama. Decent clean threads and not bent.

This all ties in with my oversize facemill thread to produce this, a fixed toolpost for a Multifix aa. It's not been without it's stresses but ultimately a nicely finished end result that works, can't say fairer than that.

Happy Christmas to you

Martin

Edited By Martin Shaw 1 on 20/12/2022 15:43:42

What an excellent result, Martin

… must have boosted your self-esteem enormously.

MichaelG.

Good job, decent tools make all the difference!

Tony

Thanks for the update martin, good to know my suggestion of Volkel worked out for you (and the facemill too)

The quality remains long after the price is forgotten.

Jim

Most of my (tap) die holders are old ones that I have aquired secondhand, they are much better than any I have bought new. Years ago I used a water pipe thread cutter (a bit like a Coventry diehead). this had 3 pins that you forced in to centre the pipe (and lock in place). It was heavy being turned by a 2' /3' handle. I have often wondered why noone makes a die holder with a similar guide. This would be 40 years ago now (at least), I think it was an old piece of kit then. It took a bit of setting up, but did a good job.