Right tool for the job?

[BADAZZGSX]

I'm having a local machine shop port my stock turbine and o2 housings out to be gasket matched. They have had my parts for like two months; so I called ,AGAIN, to see what the hold up was. He told me that the surfaces were crystalized from the heat and they were like glass. He claimed all his bits were just sliding around and not cutting much at all. Is there any certain type of bit that I could tell him to try that would maybe be easier to use. Or faster.

 

[REDBLUR]

Get a good carbide bit. I just did my O2 sensor housing, turbo, and exhuast manifold this weekend. With a high speed die grinder, alot of patients, and a good bit, it took me about 6 hours to get it all done.