Yes they work very well here too. Just not as precise as regular twist bits but they do have their uses in our repairs. They just don't work very well on the even harder steels.
This is where you just need ones that can handle Rockwell C70 specs. Those bits are very pricey for limited use. I just check on a 17/64 bit and it is over 45 usd before the shipping charges but you got to have it you don't have much of a choice so sometimes it is better just to get the replacement part.
I do have a project that I need to test the material to if one those masonry carbide tip cut the metal as a regular HS bit only dulls without leaving much more than an impression of the point in my drill press. If cuts then I can a cheaper 17/64 Carbide twist bit. It either get the bit so I can install a $.50 bushing or get the $15 bushings. I hope it works as I like to offer the guides in the finish reamer size to other techs here in the US for doing the 1/4 valve guide as the current guide only work with the counter bore reamer and is quite sloppy for the finish reamer.
