This knob is used on the airbus engine master panel (fuel cutoff)

This version is a full knob, however there is another version on my profile that has the model split and easier for some to print

You will find recess holes, these are a guide to where the grub screws need to be, you will need to drill these out further. I have also not placed a centre hole on the bottom of the knob, due to some people needing D shaped holes and others circle.

There is one grub screws at the back of the knob