A professional who assists workers engaged in operating derricks, cranes, power shovels, or other hoisting machines used to lift and move machinery, equipment, or materials, such as concrete, castings, structural steel, stone slabs, mill rolls, scrap metal, pipe, dirt, and logs, performing any combination of following duties. Responsibilities include:

• Couples and uncouples railroad cars and throws railroad track switches.
• Affixes hook, bucket, electromagnet, or demolition ball to crane, or affixes rope, cable, chain, sling, or other grappling equipment or attachments to object being lifted or to lifting mechanism.
• Places blocking, out-riggers, or screw-jacks in position to hold crane or shovel upright when lifting heavy loads.
• Places supports in position to receive load.
• Signals operator, vocally or with hand signals, to guide operator in lifting and moving loads when view from crane or shovel cab is obstructed.
• Pushes or pulls load as it is lowered, until it is deposited in desired place.
• Secures load to trucks or railcars, using ropes, chains, or bands.
• Lubricates moving parts of crane or shovel with grease gun or oilcan.
• May install extension sections to boom, using pins and cotter keys, or nuts and bolts.
• May lay track or timber runways on which tread-wheeled machines move.
• May drive truck-mounted crane from one work location to another.
• May be designated according to equipment used, attachments made, or area worked in as concrete-bucket hooker; transfer bay floor worker; locomotive-crane-operator helper; log hooker; magnet placer; pit-power shovel worker; power-shovel-operator helper; truck-crane-operator helper.
• Performs other duties as described under helper master title.