chisel information

[harry strasil]

FWIW, For those of you who are experiencing chipping chisel edges. The problem may be that they are not tempered right. If you want to try to remedy this situation, it is easy. Remove the handle from one of the chisels, then put the steel part in the kitchen oven at 350° for an hour and shut the oven off and leave it till it cools. Try it and see if it improved it. If its still too hard and chips. Do it again at 400° which is the normal tempering heat for most tools. If you polish the surface first, the color you should obtain for Wood working tools is a pale straw, (light yellow) color to the tool after tempering.

Once you get what you want, you can batch temper as many as you want at one time.

[josh bjork]

HI Harry, how many steels are affected by 300-400 degrees?

[Mike Henderson]

One problem I've encountered is that the edge of a new chisel was over hard but the body was fine. If you do Harry's suggestion, make sure you don't have that situation before you temper the whole chisel.

Mike

[harry strasil]

I think all the steels except the exotic air hardening and the S series that have red hardness. I didn't play with them.

3 to 400 degrees is the norm for tempering most tools, Quenching hardens, tempering removes some of the hardness and imparts ductility and toughness into the finished product.

normal rule of thumb is you can work (grind) and as long as you don't get the tool over 400 degrees you won't affect it. when it turns blue you have got it to hot. I am no expert, but have done a lot of heat treating of different things. mostly tools for working iron.

I do make my own router blades and some plane blades.

[harry strasil]

If you have some junk chisels because they are too hard, what have you got to lose by trying to retemper one.