D-shaft control knob

A replacement knob that pushes onto the D-shaft of a potentiometer, rotary encoder or appliance timer, with a pointer line on top so you can read its position. Enter the shaft's diameter and its across-flat size from a caliper, pick a ribbed, smooth or hex grip, and tune the push fit for your printer. An optional side hole takes a small grub screw or self-tapping screw to lock the knob on. Prints closed side up with no supports.