Machinist's Square

This small steel square is often sold in sets of three, this being the smallest. This tool is often used in a variety of settings, from a machinists' shop, to a woodshop or a jeweler's studio. I often use it to check the squareness of my chisels as I grind them on a wheel. It is also useful for laying out lines on a piece of stock or checking the squareness of a machine's blades or knives.