By the way: Wouldn’t it improve things further to have the Z-motor on top and the threaded spindle (or the trapezoidal spindle used by motoritz) with a decent fixed spindle holder sitting at it’s bottom?
Thus the motor’s bearings wouldn’t have to carry the spindle’s and the whole Z traverse assembly’s weight, and given a reasonably precise “decent fixed spindle holder” the wobble thingy should be decreased futher.[/quote]
I don’t think that make much sense. You can also let a more stable designed upper bearing holder let carry the weight. You just swap the problem upside down, since the hole frame is more stable at the buttom. And the bearings of the motor should be able to carry the z support with ease, thats not what I worry about.