Operate battery of machines to drill center holes in jewel bearing blanks.
What does a Jewel Hole Driller do?
Operates battery of horizontal, multispindle, drilling machines to drill center holes in round jewel bearing blanks: Puts molten shellac on end of work spindle and centers jewel on spindles, using small, hand centering tool. Fits drill bits in soft shellac in drill head. Trues up bit by holding bit lightly with tweezers to detect any play indicative of poor alignment; straightens bit by moving its tip slightly to eliminate play. Inserts work spindle, applies diamond dust with wire to drilling point, and removes jewel when spindle spring opens and thus indicates hole is drilled. Inspects holes for size by manually turning them on standard bit used as gauge.