HSS vs O1

[Chewy]

Making some jewelers screwdrivers. Looking for the toughest 1/8" steel. I made a couple out of O1 about 4" long to go into a handle. .058 and .075 diameter Tempered to dark blue. The tip is around .015 flat. Let me clarify the blade is 1/8" diameter tapered the last 3/4" or so to the diameter and the blade tapered on a grinder. A 5C in a collet block is fantastic for a flat square blade tip.
The HSS available with cobalt is only 2-3/4" long and I need longer then that. Carbide is available but I think that would be brittle in such a thin blade. Right now the blades are tapered but the selection will carry over to gunsmith screwdrivers in the future.
Has anybody used HSS for a screwdriver? Anything better then O1?

 

[benmychree]

Definitely do not use HSS, it will be brittle, same for carbide, of course, neither can be tempered to reduce brittleness, I'd think 0-1 would be a good choice.

 

[RJSakowski]

I have used old HSS reamers and pulley taps for small chisels . punches. etc. They will take a lot of punishment before failing. I cut a 1/4" keyway in a shaft with one made from some 1/4" HSS. I wouldn't try carbide though. Far too brittle.

 

[RJSakowski]

M2 HSS can be heat treated to increase toughness and annealed.

High Speed Steel | M2 High Speed Steel | M2 Steel

Hudson Tool Steel shares technical data associated with M2 High Speed Steel including applications

hudsontoolsteel.com

My preference for a screwdriver is that it will not deform in use. If it deforms, there is a good chance that the screw slot will be damaged as well. I would rather that it break instead as a failure mode.

 

[Ulma Doctor]

A2 steel is pretty damn good for tough applications

 

[GeneT45]

I'd favor O-1 of the two, but some good high-carbon steel hardened and then tempered back to straw is what I'd use.

GsT

 

[ericc]

HSS is only good for cutting tools. I tried to make a few hot chisels from large unwrapped end mills. Wore my striker out. In addition, they are unreliable when subject to impact. O-1 is great for hardened and tempered tools, especially cutting tools that have to be forged or machined before heat treatment. I haven't mastered heat treating HSS.

 

[K30]

Would it be too much of a pain to hollow grind them instead of taper to the tip? It really is a whole lot nicer on those teeny screws (and big screws...).

 

[WobblyHand]

Hollow ground is quite a bit nicer, if you have irreplaceable screws on some fine equipment or firearms. Keeps the screwdriver tips from camming out of the slot. I have Chapman Tools screwdrivers and in my humble opinion they are really nice. The bits are hollow ground and available in lots of sizes. They have lots of specialty bits as well, including JIS. I have no financial interest in the company, but really like the quality of their tools.

 

[Eddyde]

39 years ago, when I was an apprentice I made a screwdriver out of O-1, I hardened and tempered it though I don't remember to what color. I still have it and it still works fine.