A thumbscrew is a type of screw drive with a tall head and ridged or knurled sides, or a key-like flat sided vertical head. They are intended to be tightened and loosened by hand, and not found in structural applications. They are sometimes also cut for Phillips head or slotted screwdrivers as well as having the knurl for finger grip. Thumb screws are used in computer cases, and in other locations where easy access without tools is desired.
