Quote Originally Posted by i2i View Post
Not exactly what i meant. What i was suggesting is to drive the actual Z screw in the knee with a stepper "through a belt reduction if you require", but not through the angle drive present on the front of the knee.
I was interested in what axis' would require a belt system in order to reduce cost. I did some tests on the handwheels using a newton gauge and a lever. Here are the results I got.

Axis NM
X 1.68
Y 1.41
Z-Via Knee 8.0


I also wobbled the handles and measured how much slack there was in the screw.

Axis Slack
X 0.85mm
Y 0.06mm
Z - Via Knee 0.08mm


Im gonna do some more testing but it seems i could get away with out the belt system on the x and y and just direct drive with a 3Nm Nema 23 and use a belt system on the Z.