Here's a pic of part of a wire cutter. It cuts 3 pieces of .110" x .017" oil tempered flat wire at a time. There are three 3/4" x 1/4" square carbides. They are red in the model. The wire advances 3" out of the lower carbide through a 1/8" square mouse hole. (Yes, we have square mice) The arm then moves up and snips the wire driven by a cam follower in eccentric. Each carbide has 8 cutting edges and I would be thrilled to get a week from each edge or 200,000 cuts. That's about what I get on my other machine using round carbides, so it's not unreasonable.
The problem I'm having is the top carbide is chipping after 200 cuts, the arm carbide seems not to chip. It is C5 TiN coated. The arm is in tapered roller bearings an is very ridged. The green block behind the carbides has a fine thread adjustment screw and caps that clamp the carbides are not shown but mount using the visible holes.
Since the mechanism is already built and mounted, I'd prefer not to build a new design. Once I figure this out, the machine is done!
I have no idea what grades to try next and I wonder how much pressure to apply to the carbides.