I wonder what someone with wire EDM would charge. That seems like an ideal and cheap use. I've been dreaming of EDM lately... in a Linsey Publications type of context.

Carbide is acceptable and will get the job done, but youre going to burn up a lot of inserts getting it dialed in.

Ceramic, on the other hand, is purpose designed for cutting hardened materials.

I was tearing my hair out trying to turn a hardened 4140 piece in my lathe even running carbide. Then I picked up some ceramic inserts and it was like night and day. Immediate and dramatic improvement in surface finish and tool life.

We have a face mill that takes the same style carbide (although smaller size) that my lathe tool does and I'm very interested to see how that runs with ceramic.