Here is a knurled knob for use with a RepRap Discount LCD controller. It makes use of the Knurled Surface LIbrary V 2 by aubenc for OpenSCAD. This version includes a finger-sized dent for easy spinning. It will also work with any other device that uses a 6mm D-shaft. I recommend printing this part in ABS. Simply print, then shove onto the LCD controller shaft.