Prepare a 50mm M8 Bolt by adding a flange bearing and then a washer. Insert a cross dowel into a Cradle Base dowel hole. Line up the slot on the dowel head with the corresponding bolt hole. Insert the prepared M8 Bolt. It might be a little tricky to start. Tighten a quarter turn past finger tight. Repeat to add the other three bearings to the base. If the Cradle Base rests unevenly like an old restaurant table, just loosen the bolts, sit the base on a level surface, and retighten.
Seat the finished Leaves and Angles into the Cradle Base slots, making a V shape. For easy use, you want the skewer clamps to face the front of the scanner. Adjust the clamps until the whole cradle feels sturdy. Now you can easily unclamp and slide to fit any book spines.