rockwell hardness for skew chisel

[Ron Petley]

I posted over on the thurners forum but no takers, so I will ask here, it is slightly off topic, but non the less here goes:
I bought a old plane blade for a dollar and want to make it into a skew chisel, does anybody know the rockwell hardness for a old plane blade. It is a iron for making moldings so it is about a inch wide and has a tang and is quite thick. I know this is a might vauge in hard facts.
And what rockwell hardness is good for a skew chisel, would I have to change it.
Cheers Ron.

[Mike Henderson]

This is just a guess, but I would think that most plane blades were hardened to somewhere between Rockwell C 50 to 62 (maybe 55 to 60 if you want a closer guess). As to what you need for a skew, when hardening plain carbon steel you have a tradeoff between hardness and toughness. The harder you make it, the longer the edge will last but the easier it will chip (fracture). Also, harder steel takes longer to sharpen.

Go ahead and make the skew and see how the edge holds up when you use it. I assume you're making a turner's skew here so I would expect that the hardness of a plane blade will work well for you. Your challenge will be to shape the blade into a skew without overheating the metal. If the metal goes blue while you're grinding it, it will lose it's temper and be soft. So you're going to have to grind slow (and dip it often) or use a wet grinding system.

Good luck! Maybe one of the blacksmiths here can give you a better guess.

Mike

[Frank Drew]

Ron,

Is this an old plane blade from a Stanley type plane? That is, is it rather thin, say a strong 1/16" (less than 1/8" certainly)?

If so, I'd say that's really not enough meat for a turning chisel. For a bench chisel, it's still pretty thin but you probably won't be doing anything that could snap it in half.

As an alternative, you could find an old straight chisel and carefully regrind the edge into a skew.

[Ron Petley]

I measured it and it is a hair short of 3/8ths of a inch thick.
Thanks for your help I have it mostly shaped so I will finish it and give it a try and see how it goes.
Cheers Ron.

[Frank Drew]

Thanks for the clarification, Ron; 3/8" is thick blade --do you know what kind of plane it came from?

[Ray Gardiner]

3/8" thick. It might be a shop made molding plane made with a chisel.
Now being recycled back into a chisel? ... possible...

[Ron Petley]

I will try to get a photo of it up here, sometimes this forum does not let me post a photo.
Cheers Ron