Anet A8 z-axis threaded rod riser

These spacers have been designed to raise the threaded rods by 8mm, so that they protrude into the recesses in the top plates of the a8 frame. Without these, the rods are allowed to wobble more so than is normal. Originally I simply adjusted the height of the rods into the recesses manually, and tightened up the grub screws on the motor to shaft coupling. I found over time, that the air gap between the top of the z axis stepper motor shaft, and the bottom of the threaded rod would decrease under the weight of the x axis assembly, creating the need for constant bed levelling. This occurs because the coupling is similar to a spring, and can be slightly compressed, or stretched. The Anet couplings are designed to allow some "give" should the z axis be driven into the bed, and will stretch to some degree to provide mild relief. Down side to the design is that they will also compress under the weight of what they carry. This cures the issue.