Carbide is probably only available as an abrasive file because of cost of machining and brittle: small file teeth are formed hot, not machined. small features need to be reasonably tough.
File steel is designed to be hot-workable and fine grained (tough for small features).
Some files are machined – the surform/plastic files – which do cut metal well. I got some ‘plane floats’ recently that might be machined.
Valtitan will not cut full martensite steel – don’t try as you will mess up your expensive file quickly 🙁
Very Coarse carbide file (intended for ceramic tiles) doesn’t work well on full martensite.
Very Coarse diamond does but not for long (maybe because I press too hard… but I always repeat that mistake if that is the case). (light gray DMT, and black DMT have short life).
I think waterstones are the fastest way I have found to remove hardened steel by hand. Soft and very coarse. They don’t last long but cheap and very fast.
In the trip down the rabbit hole… did you find any full size left handed files? I wish they existed.
How about a ‘show us your files’ thread. Two of us might be interested!