Screws are more useful than nails when you need to secure wood together. Their large thread allows them to hold the timber tightly and when used with PVA glue the timber or joint is almost inseparable.

There are three main types used in woodworking and they are available with three different drive types as shown below.

Countersunk:
The countersunk head is usually the most common type used because its unique head allows it to be inserted below the timbers surface and sometimes it is covered with dowel to create a feature.

This head is also easy to use because its head helps to guide the component down. A hole should be pre drilled first though to ensure it stays straight and to prevent the timber from splitting.

Round Head:
 The round head design has a dome shaped head and therefore is not used for and is not able to be properly countersunk. They are usually used when the countersunk type isn't needed and because the head sits on the surface of the timber they can be used as a decorative feature.

Raised Head:
The raised head design is a cross between a countersunk and round head because it has both features. This allows the component to be countersunk down far enough so that the slight dome on top is flush with the timber. They can also be used as a decorative feature.

Slotted Drive:
The slotted drive head is the most basic and simple design as it is essentially just a straight groove. This drive type is very easy to use and if the correct sized screwdriver is used they are hard to strip. This design is also most commonly seen in the countersunk or round headed components.

Phillips Head:
The Phillips head is probably the most used type of drive because they allow the user to apply more force without slipping but if the correct sized screwdriver is not used they are easy to strip. These types of drives are found on any of the above components.

This drive type is also very popular to use in cabinet making or carpentry and it is also used in some woodwork joints to create a really strong joint, for example it can be used on a butt joint with adhesives.

Pozidrive:
The Pozidrive is probably the least common drive type because it requires a special type of screwdriver although a Phillips head can sometimes be used. Its design looks similar to the Phillips head but it has some extra grooves which help to prevent stripping giving it the best driving force.