Properly Grounding a Potentiometer (aka Pot)

[BrewVegas]

I'm working on an SSR build and have a question about properly grounding a Pot in the metal enclosure project box.

There is a little post sticking out of the Pot.

Screen Shot 2013-04-01 at 9.30.51 AM.png

I'm confused as to it's function. I thought it was to ground it, but when the pot is mounted the little post prevents it from seating level and the knob sits cockeyed once the nut is tightened down from the front. I plan on getting two more nuts and seating them to the same depth as the post, (or grounding down the post) so that it will sit flush when I mount thru the hole from the front.

How do other people properly mount the Pot?