Judo Chop

There's screws on the side, I feel like a tit now. Just in case that doesn't work, how do I "Roach" my knobs? (Ooh Matron.)

I bought a set of gold control knobs off my mate, who said they'd fit a P-bass or a Telecaster. When I tried to put them on my bass I noticed that they didn't have the black insert that I found inside the original chrome knobs, which seems to hold them in place. This is probably a ridiculously soft question, but does anybody know how I can get them to fit? Any help or cruel mockery would be appreciated.

I'm just over the border in Mold, how old are you guys?