Quote Originally Posted by NordicCnc View Post
The ribs would be bolted to the rear plate, top bearing plate and motor bracket, effectively forming a rigid box. Is this just adding dead weight?
Machines only as strong as its weakest point. Currently what is keeping the back of your Z axis still? Its those carriages, which are attached via a 90 degree but-joint. So I'd say those two or so screws are the weakest point! That's why I created the side plates on my Z axis to give some support to the joints.