Job Description:

• 1) Measures, marks, and etches units on side of glass tube or similar measuring devices, using calibrating device and solution of hydrofluoric acid: Fills tube with specified quantity of mercury and marks meniscus of mercury with special pen.

• 2) Covers tube with wax.

• 3) Positions tube in calibrating device, aligns needle guide with calibrated ruler, and turns locknut to hold guide in place so that exact measurement can be marked, starting from meniscus.

• 4) Turns handwheel that moves needle in back-and-forth motion to remove wax and expose glass to be etched with acid.

• 5) Realigns needle guide to next unit to be marked and continues sequence until tube is calibrated.

• 6) Removes tube from calibrating device and dips it into solution of hydrofluoric acid so that acid will permanently etch area of glass not covered with wax.

• 7) Rinses tube in cold water to remove excess acid and in hot water to remove wax.