Hi There vping,
I sold indexable ceramic, cermet & carbide cutting tools for years.
What is the Mat`l & BHN or Rc of your bushings?
If their below 35Rc; Try a "CERMET" mat`l. from "NTK" cutting tools with a "Razor sharp" cutting edge and a very small nose radii (.004R): Ex. CNGG-4304FN-Grade XT3 (80 deg. diamond but are avail. as a std. in all geometries).
Should they be above 35Rc & upwards of 63Rc; "CERAMICS" are you answer. They withstand heat 10 times that of carbide.
There`s a local rep out in the island & an excellent stocking dist. in NJ. If you want or need more info. Just post it here or PM myself.
You won`t be disappointed;
Regards, Russ