X axis of the 3d printer.
The X axis travels on the y axis along two 20mm hardened steel rails. Linear bearing are used to provide rigid travel for the stage that will hold the print head. Motion is actuated via a stepper motor mounted on the rear of the X axis plate, driving a timing belt
Belt tensioning is done by shoving the left hand bearing further left. Many complicated tensioning schemes were considered and in the end this was chosen as the simplest and by far the easiest. The end bearings were recycled from a laser printer fuser unit
The brass block is bolted to the X axis stage from the front and couples timing belt motion to the stage. I learnt from the Y axis problems with fabricating a timing belt holder and opted for a simpler mechanism this time round
The belt is hold in place by a short section of belt. This was much easier than cutting slots in the metal to engage with the belt its self.