I am making a bracket that will clamp onto a 1" OD pipe. I model it in SolidWorks, make the 3D G-code with FreeMill (just to try it) and cut with Mach3 with a 1/2" ballnose.
The resulting diameter is smaller than the 1" I need because of the 0.01 increments I have in the tool path. In other words, since the ball leaves a little material between the passes, this is enough to cause the ID to be too small to fit around the pipe.

Is there a way to predict this and model the diameter of the cut slightly larger to compensate for this effect?

Steen