Hi Frank, First, move whole part to top view, on center. Create a clean hub by CREATE-CURVE-PROJECT, projecting a straight line thru the origin on the surface. The cross section is a line and an arc. Extend the line .5 in. on the OD, and CREATE-SPLINE-CURVES with the line and arc to get a spline. Create a revolved surface with this line. Now you have a clean hub. The blades are 2 arcs, .090 apart. If you make new arcs, it will be easier to extend them. I think you can use a .250 cutter with a .0625 radius. Offset the arcs .125, and make a flat surface between them. If you do it right, it can be machined flowline. Then project the flowline toolpath to the hub TOOLPATH-NEXT MENU-PROJECT. This will put the toolpath right on the hub without moving anything in the top view. The fillets against the walls will blend into the hub, but I would leave them alone. If you machine one way towards the center, the cutter will cut cleaner, since it's moving upwards. Same method for roughing with a larger cutter. The little scrap of a fillet looks like it shouldn't be there. The left curve of the cavity needs to wrap around the tip of the blade a little bit before you create the flowline surface.

Yes, CG777, MODIFY-BREAK-SPL TO ARCS.

There's no direct lines-to-arcs converter. I'd create ARC-3-POINTS to find the arc radius, then float the arc in as a fillet, and delete the lines.

Barrel cams are best cut now with ROLLDIE. Use the SLOT option. It's also easiest to work from the flat, since ROLLDIE sort of combines axis substitution with a special offset. If you need a real cam rise and fall, cycloidal or modified harmonic, contact me.

Use a flat layout of the cam. Assuming the axis of the cam is on X, one revolution of the cam is pi*dia. Then any angle on the cam becomes a Y value by the following relationship: y/(pi*dia) = A/360. Example: dia=4, A=70 deg. then y=pi*4*a/360 = 2.443 in. in Y. To machine barrel cams, always use the ROLLDIE C-hook. It offsets for a slot from the centerline, and works nicely from a flat layout.