HSS threading tool grind

[Boucher]

Making threading tools from HSS parting blades has some advantages over using the square tool bit.

This is the arrangement that I copied after Speerchucker posted his setup over on the gunsmithing section of PM. I made a mandrel for a CBN wheel that I had. After roughing the threader on the belt sander. It just takes a quick brush on the wheel to finish the threader using the compound on the lathe.


My stash of old Rex 95 parting blades is about used up. They are sure better than the new Chinese blades that I have been getting.

[Mcgyver]

Making threading tools from HSS parting blades has some advantages over using the square tool bit.
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I would have said the opposite. There can be a fair bit of sideways force on a threading tool as you generally feed from the compound so the cutting force is one of the angled sides. The thinner parting blade will flex more in a sideways direction than the stout square bit.

In that set up, have you tilted the the bit so there is clearance ground as well?

I've sharpened lots of hss bits for V threads and Acme. Inevitably the best results imo come from finishing with a stone. The resolution of degree markings on a say T&CG aren't good enough to get a black out between the tool bit and the thread gauge...lathe compound might be a bit better...but a few minutes with a stone gets it dead on.

[justanengineer]

Im starting to think that maybe I need to build another grinder. Ive been freehand grinding bits for years and never saw a need for more than simple gages, but after the various threads about people using fancy grinders I feel almost inadequate.

I wouldnt use cutoff blades for one simple reason - I have a ton of standard square bits and few cutoff blades.