Hand Tools

Subject:
bowing.....

David Weaver
It'll bow in the right direction probably every time, though whether or not it's as constant as gradual as this would depend on process. There's a departure on my chisel vs. one professionally made (many, I should say, but one big process difference) and that is that I believe most historically made chisels would've been hardened and tempered and then most of the finish grinding done on a wet wheel, and perhaps later on, all of the bevel grinding (and maybe that was earlier, too).

I cut all of the bevels as gradual as they are shown right down to the edge as I have good heat control in my forge (but the forge is only long enough to fully heat about 6-7 inches or so of the blade, so the last bit before the tang is likely unhardened to partially hardened. These bevels and the quench differential team up to create drastic (but constant rather than random waviness) warping. I would guess right after quench, the tang would've been 1/4th inch+ off of a surface if the bevel end was held down. It's a little less than a 16th now (which i like) but I'd bet an army of catalog orderers who thinks they're going to make paring blocks would try to return any such thing as being warped.

This chisel as it is now has some carbon pooling on the surface right at the middle on the back side, but it's so far up the blade that it'll never be encountered, and that area has been hammered even though it's full hardness, and it's ductile enough to be fine. I put the chisel in a vise and push it back and forth about an inch each way (so through about 2" of travel) and it's fine with that and doesn't retain any deformation. This kind of spring is nice to have in a parer. I don't know why, but it seems to make it easier to keep them from diving. That's not proof, just a guess that could be wrong.

The chisels out there now still being made as parers, as well as the thick sided later chisels, appear to have been die forged with rough bevels made in the die striking, and with minimal follow-up grinding. I think if you can tolerate warping in production, hammer afterwards and not be forced to remove every cosmetic indication of hammer adjustment, then you can make a better chisel than you can buy of this type.

I don't know if Rob Lee or anyone else would pitch in their two cents, but I'd guess that a flexible and still hard chisel would be difficult at this point in machine tools that probably work better grinding and machining rigid blanks. The job grinders probably would've had a special backing board for anything like this to allow it to be flexible, but still support it so that it could be ground accurately.

I did most of the bevel wasting with a belt grinder and a ceramic belt as filing it wouldn't be difficult with a backing board, but I haven't made one yet. Filing it would actually be quite pleasant - the belt grinder makes it easier to overcut and I still leave a significant amount to finish with files so that it can be done accurately and there's no chance of one slip and ruination. The wonkiness at the top below the tang is how far in the lines ended up moving after file clean up, but I saw that coming after one slip up on the belt grinder. The simple remedy is just to remove more material at the top of the taper to chase the lines out a little bit and clean it up, but I was too lazy.

If I had a longer quench (I will soon), the entire length of this thing could've been heated in my larger forge and then differentially quenched just short of the tang so that there would be no warpage and bevels creating such a thing.

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