@Rockhead,
tin·ker
[ting-ker]
noun
1. a mender of pots, kettles, pans, etc., usually an itinerant.
2. an unskillful or clumsy worker; bungler.
3. a person skilled in various minor kinds of mechanical work; jack-of-all-trades.
4. an act or instance of tinkering: Let me have a tinker at that motor.