A professional who controls pressure, temperature, and water level of cooking tanks, and operates centrifuges and separators, to manufacture animal glue. Respnsibilities include:

• Admits hot water and steam into cooking tanks containing crushed animal bones, following specifications.
• Opens valves to drain glue and tallow solutions (grease) into separate vats.
• Starts centrifuge machine that separates animal oils (grease) from glue solution.
• Cooks glue solution to evaporate water from glue.
• Reads gauge of hydrometer to determine percentage of glue solid in solution.
• Disassembles plates of centrifuge, using wrench and hoisting device; and cleans plates, using brush and abrasives.
• May weigh and add specified amounts of chemical to preserve glue.
• May direct other workers engaged in cleaning tanks or vats.