30mm dia shaft 6mm comfortable knob

I made this for volume control variable resistors on my amplifier.

Outer Dia: 30mm
Shaft dia: 6mm
Shaft slot length: 20mm
Screw: M3 nut and 10mm screw (better using hex cap screw or set screw)

Print the dot in different color and glue down into the hole on the knob.
Can be printed with no support.