Steel erectors are also referred to as iron workers. Steel erectors build skyscrapers, bridges, fences, elevators, bank vaults and other structures with the use of iron or steel girders, columns and other construction material. Steel erectors are required to work at dangerous heights and with heavy equipment. Steel erectors pull, push and pry steel girders into place, connecting them with nuts and bolts or welding them. Steel erectors erect steel frames, assemble cranes, scaffolds and derricks to move and lift structural steel, buckets of concrete, lumber, re-bar and other materials. Steel erectors also unload and stack steel girders, bars and columns besides checking horizontal and vertical alignment of individual pieces using levels, transits, laser equipment, or plumb bobs, before welding or bolting pieces together.