Screwdriver - Drive Types

Drive Types

Screwdrivers come in a large variety of sizes to match those of screws, from tiny jeweler's screwdrivers up. If a screwdriver that is not the right size and type for the screw is used, it is likely that the screw will be damaged in the process of tightening it. This is less important for PoziDriv and SupaDriv, which are designed specifically to be more tolerant of size mismatch. When tightening a screw with force, it is important to press the head hard into the screw, again to avoid damaging the screw.

Some screwdriver tips are magnetic, so that the screw remains attached to the screwdriver without requiring external force. This is particularly useful in small screws, which are otherwise difficult to handle.

Many screwdriver designs have a handle with detachable tip (the part of the screwdriver which engages with the screw), called bits as with drill bits, allowing a set of one handle and several heads to be used for a variety of screw sizes and types.

Many modern electrical appliances, if they contain screws at all, often use screws with heads other than the typical slotted or Phillips styles. Torx is one such pattern that has become very widespread. The main cause of this trend is manufacturing efficiency: Torx and other types are designed so the driver will not slip out of the fastener as will a Phillips driver. (Slotted screws are rarely used in mass-produced devices, since the driver is not inherently centered on the fastener.) A benefit/disadvantage of non-typical fasteners (depending on your point of view) is that it can be more difficult for users of a device to disassemble it than if more-common head types were used, but Torx and other drivers are widely available. Specialized patterns of security screws are also used, such as the Line Head (LH) style by OSG System Products, Japan, as used in many Nintendo consoles, though drivers for the more common security heads are, again, readily available.