A tool used to tighten or remove screws. Screwdrivers are identified by
the kind of screws they fit. The commonest types of screwdrivers are the
slotted (also known as straight-edge,
flat, or standard tip) and the Phillips head. More specialized
- Allen or hex. This works with screws that can also
be operated with Allen or hex keys. It is suitable for socket-head screws
that are recessed.
- Robertson or square. This has a square drive that
gives high torque power and can reach screws that are sunk below the
surface. Robertson screwdrivers are usually color coded according to
- Clutch–drive. This has an hourglass-shaped tip that
is especially useful when extra holding power is needed, as when working
on cars or appliances.
- Torx. This has a star-shaped tip that is useful for
replacing such parts as tailgate lenses. It is widely used in automobile
repair work. Torx screws are also used in household appliances, as well
as lawn and garden equipment.
| Some types of screw
A screwdriver is most effective when the width of its head matches the width
of the slot in the head of the screw. Among the most generally useful screwdrivers
are a quarter-inch slotted and a number two Phillips head. However, it is
a good idea to have a complete set of screwdrivers to match the variety
of jobs can crop up around the home and elsewhere.