Screwdrivers: Drawn Wire, Cold-Formed Tips and Turned Handles

A screwdriver's shaft, or bar, starts as coiled steel wire drawn to size and annealed, about 1,350 °F (732 °C) for 12 hours. It is straightened and fed to a cold-forming press that cuts it to length and forms the tip and the "wings" that lock into the handle; Phillips tips have their four grooves cut in a separate operation. The bars are hardened in an in-line furnace at about 1,555 °F (846 °C), dropped into an oil quench and tempered at 450–500 °F (about 230–260 °C), then nickel-plated. Handles are usually cellulose acetate, extruded into bars, turned to shape and drilled, and the bar is pressed hydraulically into the handle.