The Fitter’s Squares

The fitter’s squares are made of high carbon steel and are used for checking the squareness and for marking off lines at right angles to an edge. To check for accuracy, it can be checked against a master square and scribe a line down using the blade as the guide. Any error will show up as twice the actual error by reversing the square on the master square.

FIGURE

Just like any other hand tool, these squares should also be kept clean, lightly oiled and stored in a proper place.