Quote Originally Posted by JAZZCNC View Post
I wouldn't use those spacer plates and just buy thicker Material because your introducing several more operations into the job but more importantly increasing the chance for error.!! . . . . Unless Your getting the work done for free won't be saving any money and will probably be cheaper because of less cycle time involved, also it won't be much lighter.
I was not enthousiast with those spacers but this is in my opinion the only way to adjust the position of the rails afterward... Because the lower Hiwin blocks are fixed first with positon guaranteed by the machining of straight edges, I still need to be able to adjust the rails... And here is the role of the spacers.

Related to the reduction of the thickness of the motor holder, this is necessary due to the relative short length of the axes. Mechanicl strength will still be plenty because belt tension effort combined to pulley position is only generating low flextural torque.
However, have you some suggestions (little drawing appreciated) about how to design this part in a different way ?

For the Z axis the position of the posts have been checked for sufficient clearance for the belt path. Of course this introduce limitations with the size of the pulley but I don't expect to change from ratio 1:1

Thank you very much for all your valuable comments making this thread alive.