A professional who tends machine that attaches protective metal strike-plates to wooden segments of assembled folding rule. Responsibilities include:

• Mounts reels of metal strip on machine spindles and threads strip ends through feed mechanism.
• Holds unfolded rule against guides and starts machine that cuts off, forms, and fastens pronged protector-plate to each segment of rule.
• Removes spilled and jammed plates from mechanisms, using screwdriver.