I decided not to motorize the handle that lifts the knee. I’d need an enormous motor for starters, and stepper motors don’t go much over 4nm. The weight of the table, cross slide etc. presents the first problem.
The second issue is the handle driving the knee, which exits at an angle (not perpendicular) with no end cap on it. The mill would have to be accurately drilled and tapped, in situ, to mount the motor. Lots of problems to overcome.
Instead I’m driving the quill to achieve my Z axis. I’m limited to 4" of CNC travel, which should be enough. I can also manually drive the Knee. I went for the largest pulley to get the most torque and steps per mm.
Mounting the motor for the Z was a bit of a faff, but I’m there now. Just a case of calibration and fine tuning now 🙂