Differential heat treating folder blades

Dec 10, 1998
I wanted to know if I differentially heat treat a folder blade will the lock area, lets say for a liner lock, and pivot wear out faster? I know that it would probally take a lot of use to wear out but it made me think.
Chuck, Yes the detent ball will wear a groove where it runs on the blade eventually, maybe sooner than we think.
I differnentially heat treat all my 52100 folder blades. As long as you harden the ricasso area too you'll be fine. Bruce is correct about the detent ball rapidly wearing a groove and galling if you leave the ricasso soft.
I use a "limiter plate" in my quench tank, and hold the blade about where the thumb-bob will got, then I rock the ricasso back into the oil and achieve hardening. It's worked great so far. :D
Ed, do you get a visible temper line? I found that the temper line usually sits about 1/16 to 3/16 above the oil level. Do you temper the back with a torch with the edge in water?
I have been thinking of doing this as a folder with lightly etched 01 or 5160 blade showing the temper line, antiqued bronze or damascus bolsters with ivory handle will be something to brag about.
Yes, the temper line will be just a shade about the level of the quench.
I DO NOT try to soft back draw the blades. A couple of recent incidents have me dead set against fully hardening a blade and then using a torch to "try" and soften the spine. I basically edge quench the blades, trying to keep the spine temp down, and only getting the portion(s) of the blade I want hard, to critical temp.
Once the blade is finished, a light etch in ferric will give a great temper line!