Gnome, Goblin and Mechagnome hunters automatically know how to tame Mechanicals. Hunters of other races must acquire the skill from a Mecha-Bond Imprint Matrix, crafted by Engineers who have at least 1 skill point in Legion Engineering.
Located in The Dormitory, Gnomeregan (Dungeon). A prismatic card reveals a hidden room. He'll need a shocking kick before he becomes tameable. We're not yet sure of the minimum level required to tame this one!