Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

When cutting my "V" grooves I always work back and forth, side to side, as just jamming the cutting bit straight in is prone to produce serious chatter once you get a ways in. I always finish my groove with a side to side cleanup, and so I do end up with something of a small flat in the bottom of the groove. However, I have never done the math to figure exactly how wide that flat should be, in order to fit whatever diameter belting is intended to be used, so I suspect that I'm not getting the max traction that the graph suggests is optimal.