Differential heat treating folder blades

[Chuck Gedraitis Knives]

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.
thanks
Chuck

 

[Bruce Bump]

Chuck, Yes the detent ball will wear a groove where it runs on the blade eventually, maybe sooner than we think.

 

[Ed Caffrey]

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.

 

[RSA Knifemaker]

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.

 

[Ed Caffrey]

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!