Screw

Screw are probably the most commonly used threaded fastener in aircraft. They differ from bolts in that they are generally made of lower strength materials. Screws are typically installed with a loose-fitting thread and the head shapes are made to engage a screwdriver or wrench. Some screws have a clearly defined grip length while the others are threaded along their entire length. There are three basic classifications of screws used in aircraft construction : machine screws which are most widely used, structural screws which have the same strength as bolts and self tapping screws which are typically used to join light weight materials.
Figure 1 shows the example of types of screws used on aircraft.

(Figure 1)

Types of screws used on aircraft.