Motors and Movement - Printing in Plastic: Build Your Own 3D Printer - page 216

Figure 13-6. Tighten the belt pulley over the bearings with an Allen wrench.
Lay your 3D printer frame down with the Lower Structural Sides pointing towards you. Insert the X-
Axis Motor Mount as demonstrated in Figure 13-7. Push it as far as possible so that the 1-1/2” machine
screws holding the bearings are touching (or almost touching) the notch cut into the Table Bearing
Support.