Straightening chisels

[Josko Catipovic]

I found a set of Sorby mortise chisels at a yardsale. A few narrower ones seem to be slightly bent - perhaps a 5 degree angle between the blade and handle. I assume it was from overenthusiastic levering. The blades seem to register fine along the bottom half. Is it worthwhile straightening these, and how would you go about it? My temptation s to set them in a vise and gently tap the handle in the right direction, but thought I'd ask if anyone has delalt with this before. Thanks in advance.

[Frank Pratt]

Chisels are made of pretty hard stuff, so I'd worry that trying to bend them might break them.

[Jim Koepke]

I found a set of Sorby mortise chisels at a yardsale. A few narrower ones seem to be slightly bent - perhaps a 5 degree angle between the blade and handle.

Sounds like a great find. If you can post images it might help in this case.

Are the handles original?

You might try removing a handle before trying to straighten these. It could be a handle improperly installed.

Some of my mortise chisels are laminated. Most of the metal (carrier or shaft) is a softer steel or iron and the hard part is a thinner piece forge welded to the carrier metal. These can become bent near the handle.

Make a crooked handle to balance a crooked chisel?

jtk

[Bob Glenn]

Frank is right, if the chisel is hardened where the bend is located, you could break the chisel trying to bend it back. Best to remove the handles and anneal the iron, then bend it to your specs. the blade will then have to be re-hardened and tempered.

[Jim Koepke]

Frank is right, if the chisel is hardened where the bend is located, you could break the chisel trying to bend it back. Best to remove the handles and anneal the iron, then bend it to your specs. the blade will then have to be re-hardened and tempered.

Is it possible to keep the blade end cold while the handle end is heated?

Would holding the blade in a vise sink enough heat long enough to correct a bend?

jtk

[justin sherriff]

I just picked up a old chisels and it was bent a bit and it did not take much to bend it back. I put it in the vise and pulled a bit and then flat on the bench with a few taps with a hammer to finish it off.
it was bent sideways to the edge.

[Edward Dyas]

I found a set of Sorby mortise chisels at a yardsale. A few narrower ones seem to be slightly bent - perhaps a 5 degree angle between the blade and handle. I assume it was from overenthusiastic levering. The blades seem to register fine along the bottom half. Is it worthwhile straightening these, and how would you go about it? My temptation s to set them in a vise and gently tap the handle in the right direction, but thought I'd ask if anyone has delalt with this before. Thanks in advance.

Chisels can be awful brittle sometimes. I had a small one break in two and go through my hand onetime. It just snapped like a twig. What ever you do to straighten them will be risky so don't do it if it will upset you to break one. Sometimes you can put a chisel in a vice and shem it where you can bend it back when you tighten the vice. The safest way would be to remove the chisel from the handle and heat it and straighten it but then you would need some blacksmithing skills. The chisel would then need to be tempered and annealed again.

[Scott Winners]

Is it possible to keep the blade end cold while the handle end is heated?

Would holding the blade in a vise sink enough heat long enough to correct a bend?

jtk

I don't know your local answer to this, but my local blacksmith works with me when I am not in a hurry. When I take him a thing, or things, and mention I am not in a hurry he will get my box of old axe heads for instance annealed while he has the forge hot for something else anyway. Then I go pick my annealed things, do my shaping, take them back for tempering when he has the forge hot anyway. When I am not in a hurry I get my old axe heads annealed for about free and tempered for 15-20 bucks each. I am sure if I want them tomorrow the price will go way way up.

[Stewie Simpson]

I found a set of Sorby mortise chisels at a yardsale. A few narrower ones seem to be slightly bent - perhaps a 5 degree angle between the blade and handle. I assume it was from overenthusiastic levering. The blades seem to register fine along the bottom half. Is it worthwhile straightening these, and how would you go about it? My temptation s to set them in a vise and gently tap the handle in the right direction, but thought I'd ask if anyone has delalt with this before. Thanks in advance.

Sounds like the softer steel within the tang of the chisel has been bent out of alignment.

[Josko Catipovic]

Thanks folks. I put the blades in a (metal) vise, slipped a pipe over the handles, and they straightened right out. Hopefully I didn't weaken the metal much.

[Jim Koepke]

Thanks folks. I put the blades in a (metal) vise, slipped a pipe over the handles, and they straightened right out. Hopefully I didn't weaken the metal much.

Try to hit them as straight on as you can to avoid them bending again.

Also remember the sharpness of the edge helps to reduce the degree of walloping needed to cut a mortise.

Mortise chisels are my only chisels that are intentionally sharpened with a bit of convexity. One of the better descriptions posted here on the subject suggested a 25º bevel with a secondary bevel or 30-35º. Over time, it tends to become convex with repeated sharpening.

jtk

[lowell holmes]

I would experiment with one chisel. I would heat the bend gently with a propane torch and try straightening.
I think if you put it in a metal vise you could flatten it.