An adjustable tensioner to keep the wheels firm, but not binding, in the vertical slots of a Delta style printer (Kossel, Griffin, Cerberus, etc.).Printing with >20% infill should be sufficient. Use M3 hardware for adjustments. The scad file is attached so it can easily be scaled for other carriages. Use the screw to adjust the tension so there is no Non-Z movement but not too tight creating unwanted friction.