Al,

I thought it might be done with the C-axis too, however, in the latest version of Mach3, there's a place to specify the axis of rotation (X, Y, or Z) for the A-axis. It's under Config->Toolpath->Axis of Rotation. I don't think it is extra work for the Mach team, since they would simply plug in different axis DROs to the same feedrate formula, as follows:

X-axis rotary feedrate in deg/min = (360 * IPM) / (2 * PI * (SQRT(Z^2 + Y^2) - T))

Y-axis rotary feedrate in deg/min = (360 * IPM) / (2 * PI * (SQRT(Z^2 + X^2) - T))

Z-axis rotary feedrate in deg/min = (360 * IPM) / (2 * PI * (SQRT(X^2 + Y^2) - T))

OK, the following g-code is a example of "turning" the outer diameter of my part. It will "plunge" sideways at 5 IPM, then rotate 360 degrees at 5 IPM, and repeat. However, I must specify DPM (degrees per minute) for A-axis moves, instead of IPM (inches per minute). The conversion is done with the formula (above). It assumes Mach3 is zero'd to the center of rotary table. I used a MS Excel app to generate the g-code. However, Mach3 could very easily do this math, and probably should be doing it.

`;TURN OUTER DIAMETER OF PART`

;TOOL RADIUS IS 0.15625

N14 X0.469 F5

N15 A-360. F915.9997

N16 X0.4665 F5

N17 A-720. F923.5297

N18 X0.4639 F5

N19 A-1080. F931.1845

N20 X0.4614 F5

N21 A-1440. F938.9673

N22 X0.4588 F5

N23 A-1800. F946.8812

N24 X0.4563 F5

N25 A-2160. F954.9297

;FINISH

N27 A-2520. F954.9297

Rick