swing a spanner

To work as a mechanic or mechanics apprentice. Not to be confused with the useless fuckwits in admin who like to use the saying to describe writing with a pen.

Ask Bob to fix your car, he can swing a spanner properly

Fundi

A South African term for an expert or a master in a certain subject or task.

Useless member 1: Hey can you help me put this on my head
Useless member 2: I don't know how to do that, ask John, he's the fundi.