A professional who operates hydraulic-pressure-auto-frettage machine to improve physical characteristics and to detect physical weakness of machined artillery barrels, following specifications. Responsibilities include:

• Plugs muzzle end of barrel, sets barrel in vertical container of frettage machine, and tightens clamps to lock barrel in place.
• Connects water pressure pipes to machine, starts water pumps, and moves controls to apply hydraulic pressure to barrel bore to expand bore to specified diameter.
• Observes pressure indicators and records pressure and time at specified intervals.
• Fastens cables around barrel and signals overhead crane operator to remove barrel from machine.