Terms of the Trade: What Is a Speed Square?

A metal speed square.

This measuring tool, also called a rafter square or triangle square, is intended for carpentry, but it can also be a valuable measuring tool to have in your arsenal whether you do a lot of woodworking or not. It offers multiple measuring applications including a miter square for making 45 degree angles, a Try square for measuring perpendicular lines, and a protractor for making common angles. The speed square also includes a standard ruler and line scribing guide.