Nothing Japanese this time - Re-shaping chisels

Re: Nothing Japanese this time - Re-shaping chisel

mikew

>I don't think there was a standard for how far up they were hardened.

Most of my vintage chisels are lamenated Butcher firmers. So it's easy to tell.

I have a few vintage 750s. They are hard just about up to the socket--someone in the past tried to straighten a couple of them and cracked them about 1/4" below the socket.

Take care, Mike

Re: Nothing Japanese this time - Re-shaping chisel

Dave Burnard

>just do a scratch test with the corner of a file in the area you're interested in.

Re: Nothing Japanese this time - Re-shaping chisel

thomd

>Dave, spoken like a toolmaker.

Another way of thinking about it is they had to heat the socket or tang hotter to forge them than they did the edge to harden it. That isn't necesarilly conclusive since sometimes they feed the tempering heat through the tang or socket end, but still, it isn't necesarilly the case they did that if they were being made in quantity. I've seen pictures of old factories with hammers the size of a small house so they could heat and forge the whole unit from a series of dies in one strike.

A bit below the makers mark...

Scott Burr in Ben Lomond, CA

>For most I've seen. Some older tang and pig stickers are marked at the base of the chisel. The file test or seeing the forming of the blade is probably the best bet.

Use a tungsten engineers scriber

david charlesworth

>Engineers scriber, carbon or tungsten will show the softer area as well.

Does it skate or bite under medium/firm scratch pressure?

Same test shows where hard part of old plane blades ends.

David Charlesworth

Re: Nothing Japanese this time - Re-shaping chisel

Dave Burnard

>"Another way of thinking about it is they had to heat the socket or tang hotter to forge them than they did the edge to harden it."

Thom - I'm not sure what you're getting at here? Heating the socket end hotter during forging, in and of itself, won't make it softer later on. Are you thinking about decarb?

They probably heated the whole chisel blank hotter than the hardening temperature during the forging process. Then for hardening they may have kept the tang/socket end out of the heat and/or didn't submerge it in the quenching medium. Or as you said they might harden the whole thing and temper the tang/socket end back.

Re: Nothing Japanese this time - Re-shaping chisel

thomd

>My point was it may have all been hardend during the forging process that sometimes consists of heating the whole mess to press it in various dies, these aren't necesarilly hand made chisels, and they will use enormous hammers and dies to form the chisels, and also sometimes treat the whole thing as one for HT, maybe just toss it in a barrel of water.

Agreed 

Dave Burnard

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