If you want to get rid from z axis wobble or make a drill press or mini cnc mil, using this mod!There are 2 variants: for M6 and M8 screw. if you want to make a mini-cnc use 2 isolator for each screw - one isolator set at the top, the other - bottom (see the last 2 foto) I`m using isolator for M6 screw. I printed at 0.3mm layer height, 0.4 infill, 2 perimeters with standard printrbot. My printer calibration is not perfect so I have added the dwg (Acad Inventor) files encase any changes need to be made.