In Military Aviation Engine & Airframe technicians (mechanics) are know
as Blackhanders for obvious reasons. The rest , Radio, Instrument and
Electrical are known as either Whitehanders (*******s never get dirty)
or Coneheads as it takes an alien to figure out that stuff !! These
days the terminoligy is slowly creeping into the other trades. It is
not an insult, just rival banter among tradies. Blackhanders are proud
that they look like they work for aliving and coneheads are pround not
to need a shower before going to the pub after work.

Also thanks everyone for the advise and ideas. I will check it out over
the weekend.