Thread: whats this line here on my chisel ?

Just a stab in the dark here, but it could be from when the blade has been heat treated for hardening.

I would guess it is the laminated edge between the hard (higher carbon) tool steel and the softer mild steel hilt.

Could be just the half way mark to remind you that you need a replacement in the next 15 -20 years.

Jake, I have a German wooden plane blade that has three laminations like that. I think it is a join from a softer to harder steel.

On the plane blade I mentioned, it is about 1.5mm thick at one end and nearly 4mm thick at the other. It must have taken a lot of effort to make that blade.

Originally Posted by apricotripper

come accross this occationally, and I've always been curious as to why its there....

lapping out all the rust pits from an old 2" stanley chisel I bought. . Can see just under half way, there's a line going straight across from one side to the other.

some kind of lamination line ?... does it mean that business side of the blades harder than the other side. Is that the idea

I remember seeing a similar line in a plane blade once that was intended for drywall (I was told)...It had a harder steel at the tip, which I remember took longer to sharpen.

At a guess I would say it is the quench line ,I have seen it on my Titan chisels also and can only put it down to where the chisel is immersed in the oil when quenched for tempering .It's more visable on some of my chisels that others.

Kev

I'll vote for the change in material. IIRC, swords are sometimes made that way too; hammer welding at the forge vs. stick or other welding.

Joe

A forge line is somewhat curved as the metals infuse unevenly... I vote for the Quench line from the heat treatment.

Opinions only here....

My vote goes for quench line as well. Not sure though.

the lines dead straight, so a quench line sounds right. But what confuses me there is when I quench small blades I don't get that line. Maybe it was just done differently.

anyway, its not important. just curious.

thanks for the ideas.

Interesting photo, trying to think if I've noticed similar!? Depends how old the chisel is. I don't think new ones are made with two different steels, they're just cast and forged from one billet of alloy steel. A quench line is probably more likely, and a dead straight line would indicate some production line process.

Cheers,

I've noticed the same thing on one of my Titan chisels.

I can think of a couple of things. My best guess is it is from the heat treating process and represents a difference in steel structure. I would guess if you tried filing on either side of the mark the working end would resist the file more than the handle side. There are a few ways this effect can be achieved during heat treat and it is impossible to know what one produced it without knowing exactly how it was heat treated.

I do have an old draw knife that is laminated (i believe forge welded) that has a straight lamination line but it is more distinct than that one.

ron

Ta guys.

Didn't seem to get much more resistance to lapping on one side or the other..... rust pits so deep been lapping with a 40 grit....determined to get this one last pit near the edge out...

but I don't know.

will go through the grits to try and see my reflection...get it razor sharp....probably end up taking it to work, just to have that bloody apprentice use it for levering out nails while I'm not looking no doubt

Yep thats the quenching line, seen itvplenty of times on chisel and plane blades.
most certainly isnt a lamination.
if you are laminating a blade it will be a the face and back you are laminating.

I have a laminated stanley plane blade that shows both the laminating and a quench line. when you look at it it is obvious which is which.

cheers