A professional who tends machine that washes, bleaches, dyes, rinses, and dries warp yarn in rope form: Weighs chemicals and dyes, according to formula, and dumps ingredients into mixing tank.

• Turns valves to admit steam and water into tank, and stirs solution with paddle.
• Turns valves to release dye mixture into vats.
• Sets drying can thermostat at temperature specified for count of yarn to be dried.
• Mounts ball warps on rack at front of machine, using hoist.
• Ties yarn to leader to thread machine.
• Observes yarn passing through units of machine to detect yarn breaks or tangles.
• Stops machine and untangles snarled yarns or ties broken ends.
• Compares sample of yarn with standard to determine if dyeing meets specifications, and notifies dye weigher if specifications are not met.
• Observes level of liquid in vats and adjusts liquid flow to maintain specified level.
• May be designated according to dye used as indigo-vat tender, warp; or according to process as warp-bleaching-vat tender; warp-scouring-vat tender.