Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4206617.

EC11 Rotary Encoder knurled knob 6mm inner diameter

22.03.2021 Added variations for D shaft encoders.

18.03.2020 Added a new revised design in 3 diameters: 16mm, 25mm and 30mm. All of them are 16mm tall.

The knob pictured above was printed at a 0.28 layer height, bottom part on the bed, and it had the top part sanded down.

If surface finish doesnt matter much to you, I would suggest printing it with it's top facing the bed, this way you wouldnt need any supports.