There is no cheap 90degree tool that will fit in a 47mm bore. Not that I know of anyway.
I wonder how people can fry a dremel (real or imitation) in such a short time. I bought my multi in 1999, and it's still running fine after porting 200+ cylinders with grinding stones... I also have 3 $20 Kinzo machines (I hate changing buds
) and so far so good.
I suggest looking at
www.widgetsupply.com for cutters and stones. They have countless shapes/types, and are cheap.