[Al_The_Man]

I have a few older tool holders left from a larger lathe that I still have inserts for, I am think of machining these down to fit the present tool post.
What grade steel are they normally? They do not appear all that hard.
Al.

[GaryCorlew]

Hey Al,
I get the chance to answer a question for you, for a change, I have machined a few they are not hard. A couple seemed to be hard anodized or a very thin hardening so no, not bad at all.

[HuFlungDung]

I'd guess they are something equivalent to C4140. While not file hard, they might be Rc35 or so, enough to kind of take the sharp edge off a bandsaw blade.

[Al_The_Man]

Thanks Guys, I may try to take the larger ones down with a saw before machining.
Al.

[skullworks]

Many are made from 8620.

[CarbideBob]

In my shop, almost all (90&#37 are 4140, 36-48 Rc depending on who I'm making them for.
8620 is very rare to see nowadays in lathe tools, usually only milling tools and not used all that often. It is common in collet holders

KM type stuff runs harder so the shank doesn't get deformed from clamping chips in the connection. Same with milling holders, although the best stuff gets hard chromed and ground on the shank.

Really cheap square shank stuff is just 4140-pre heat (as low as 30).
Almost all can be cut down with a conventional bandsaw. Easily machinable with carbide.
Lathe cut off blades are a different story. Wide variety depending on source. Some as high as 62 Rc.
Bob