A replacement knob for old style dimmer switches.
Inner stem diameter is 6.28mm, not including notch cutout. I'm not certain that this is the correct measurement as I made this for someone else and based measurements on a broken knob. If someone can please measure the stem diameter and let me know please I could adjust it if necessary.
Update 2016-04-14: I have uploaded a version, V2, that gives a little more clearance around the 6.28mm shaft, the hole measuring a diameter of 6.34mm.
0.1mm layer or lower recommended.