CKKIII and ground question

I hope I haven't created a needless thread, I couldn't get a definitive answer from my search.

So, I want to case up my CKKIII. Here's where I'm at.

The mounting positions for the jacks and volume potentiometer are plastic. I will connect all the signal grounds together.

The mains earth will be connected to the metal parts of the case.

Since I want to keep the signal and power grounds separate the CKKIII board will be isolated from the chassis. AFAIK I don't have a reason to connect them and this is a good idea to minimize interference from the mains earth.

Assuming the above all makes sense, what do I do with the 'chassis' ground on the potentiometer? The clue's probably in the name (!) but where I've seen it connected to the chassis, the signal ground has also been connected and the case has been metal.

What happens if I leave it floating? Why should I connect it to signal/mains ground?

TIA.

Thanks for the reply. I have seen that diagram on the AMB site but it applies to a metal case and connecting the signal and mains grounds together. I'm trying to understand what the correct solution is if that's not the case.

We may be talking slightly at cross-purposes but in the end I've come to the same answer.

AIUI, the point of grounding the volume potentiometer is to reduce the effects induced currents in its metal body (especially the metal rod?), which presumably could be transmitted to the pins, or maybe surrounding wires.

Therefore, ground to chassis/mains earth if possible, or leave floating and hope for the best. Connecting to the signal ground would potentially induce the interference in the signal.

A belated update. The discussion regarding the potentiometer ground became academic, as in the end I had to connect the signal and power grounds to remove noise.