Get one at Iron island.
no
go to iron island
Trade Onix to someone with metal coat attached.
make syther hold a metal coat and link trade it
Catch a Scyther. Then get a Metal Coat. Attach that to Scyther and then trade.
Yes there is a way. You get a metal coat and trade it.
Trade your Scyther while it is holding a Metal Coat.
you gotta give metal coat to scyther and trade that's the most easyist way
the Pokemon that evolve with metal coat are steelix and scisor
A Metal Coat is given out by Byron after obtaining the National Pokédex.
He doesn't evolve by level-up. You must trade him whilst holding a Metal Coat.
The Metal Coat is used for giving to your Pokemon (such as either Onyx or Scyther) and trading it (it would probably be best to trade with a friend though); because as you probably already know some Pokemon evolve by trading or giving them items then trading them.