A corner notcher is a sheet metal working machine used to cut out a 90deg section with L shaped blades.
The corner on a sheet of metal can be cut out to provide clearance when the 2 sides may be folded up such as in a shallow tray or box.
According to our needs can be constructed to made cuts at L or radius shape.
I haven't an eccentric press so I use it with my little hydraulic press.
My needs are from 0.35 to 0.60mm steel and stainless steel and can do the job easily.
For blades I have use some pieces of hardened steel.