Printrbot Simple 1405 Z axis wobble stabilizer and z-ext acme nut

thingiverse

I'm currently using version 3, which features a slotted design that allows for some tolerance when dealing with varying print quality. The 8mm model works well on most printers, but if your prints are exceptionally wobbly or inaccurate, an 8.2mm version is available, which provides less of a snug fit over the bars. Despite earlier improvements from adding the top cap, rebuilding my printer to replace the Acme Z-nut led to subpar sidewalls again. However, with adjustments to the Z-coupler and precise re-seating of the Z-rod, I achieved better results. A small separation (less than 1mm) between the motor shaft and Z-rod is now ideal, allowing for multiple attempts at proper alignment during test prints. Version 2 utilizes a screw-on shim to prevent cap detachment while holding the rod more securely in place. Additionally, a revised Z-axis connector reduces slack along the threaded rod, aiming to rectify banding on prints. By wrapping tape around the shim, it helps keep everything in place and tightens the snugness of the fit. Another step taken towards minimizing banding was introducing a gap between the motor shaft and threaded rod within the Z coupler, yielding approximately 1mm of springy movement when pressed down before reaching the shaft. This can be seen in the image attached from Printrbot's webpage.