Features

• A screw is a simple tool that consists of a metal head and shaft. The shaft has an inclined plane that spirals around it either counterclockwise or clockwise. This inclined plane is called the thread of the screw.
  
  

Function

• Screws are most commonly used to fasten one object to another. Different screws do different jobs. A jackscrew can lift heavy objects. A good example is the jack that is used to lift a car to fix a flat tire. A vice is another type of screw.
  
  

Sizing

• Screws come in different sizes that are indicated by a number on the box. Screws do not change in length as the sizing number goes up. As the number increases, screws become wider and thicker.
  
  

Driver

• The driver of the screw refers to the type of indentation at the head of the screw. The two most common types of drivers are the flathead and the crosshead. The flathead consists of a straight indentation, while the crosshead has a cross-shaped indentation.
  
  

Pitch

• The pitch of a screw refers to the degree of the thread, or inclined plane. The pitch of a screw is determined by a number, just like the size.