screwdriver

A screwdriver is a hand tool used to drive or remove screws by turning the screw head. It typically consists of a handle attached to a shaft with a driving tip that fits the corresponding screw recess. The handle is designed for grip and leverage, often made of plastic or wood with a rubberized overmold; the shaft is usually steel and heat-treated for hardness, and the tip is machined to fit the screw head precisely.

Common tip types include flat-head (slotted), Phillips, Pozidriv, Torx, and hex (Allen). Other profiles such as square (Robertson), Tri-wing, and various security or tamper-resistant heads are used for specific fasteners. Screwdriver sets may use fixed blades or interchangeable bits. Precision screwdrivers are smaller and used for electronics and watches, while insulated screwdrivers have handles rated for electrical work to reduce shock risk.

Design varies by purpose, with short, long, or stubby handles and blades sized to match screw dimensions. Magnetic tips help hold fasteners, and some drivers include reversible or interchangeable bits to cover multiple head styles.

In practice, users should select the correct type and size to minimize cam-out and damage to the screw. Never use a screwdriver as a chisel or pry bar, and avoid exposing non-insulated tools to live electrical circuits beyond their rating. Proper maintenance includes keeping tips sharp and clean, and storing tools in a case or rack to prevent loss and corrosion.