'Baby Steps' Bed Leveling Knob

Ender printing beds (and many others) use M4 x 0.7mm pitch threads for leveling. This knob has seven sides so turning it from one facet to the next moves the table up or down exactly 0.1 mm. Use 'Baby steps' to determine bed error, then turn the knob the correct number of facets to get table height just right. Paint one facet a contrasting color to make it easier to see changes if/when they vibrate loose.