Choosing Screw Sizes

Screws are a useful tool for numerous construction projects, and selecting the right screws is essential to ensuring they stay put and don’t cause unnecessary damage. Screws come in a variety of types, materials and sizes to fit many different applications. Choosing the correct screws isn’t difficult, but it does involve a few considerations like gauge, length and the material they are going into.

The basic measure of a screw is its gauge, which is the external thread size. This is measured in inches and is typically listed as a number with a prefix of either “#” or “” (depending on whether you’re using the imperial system, which is still prevalent here in Austrlia, or the metric system that is slowly displacing it globally).

Screws also have a pitch which is the distance between individual threads. This can be found by using a thread gauge that has strips with various sizes of thread cut into them, and you systematically work through the different thread sizes until you find one that matches the pitch of the screw’s thread.

The last factor to consider is the length of the screw, which is also measured in either inches or mm. The length of a screw depends on how deep the screw will be going into the material, and how much weight it will need to support. Thicker or heavier materials require thicker screws, and fine pieces can benefit from a shorter screw. 1/8 in to mm