Simplest Anet A8 Bed leveling knob

thingiverse

For simple bed calibration on Anet A8, just add a spare M3 nut to the knob. Unscrew the wingnut and screw your knob with the nut in place. This takes only a few seconds of setup. After that, you can adjust your bed with high precision using the tip of your fingers, requiring almost no effort at all.