polsim: 15% overhang if 25% overhang if 0% overhang. 50% tool diameter area is ground away the simulation is quite contradictory to what they try to achieve - a spherical surface Is fixed post machine a good grinder? from another CN post, Tucker512 is polishing a 8 inch convex surface, 100% tool with 19% overhang(1.5 inch) polsim: which is quite similar to same y offset, with 70%D chordal stroke mark cowan CLL, for polishing his 19", use 15% overhang plus +/- 2 cm stroke