Today, we’re taking about the Swanson Speed Square. A speed square is an essential DIY tool for woodworking. Invented way back in 1930, the popularity of the Swanson speed square has grown substantially over time.

The speed square is a rafter square, miter square, try square, scribing guide, protractor and, perhaps most usefully, a good saw guide.

Instructions to use a speed square:

As a Saw Guide: You simply hold the speed square base against the lumber and align the guide rail on your circular saw (being sure to keep your hands clear of the blade) to make clean straight cross-cuts.

As a Protractor: Simply hold the base against a flat surface and find the desired angle marking.

To Find Rafter Angles: The primary use is to find the angle for rafters. Calculating the correct angles for a rise to run ratio is simple with trigonometry, but the speed square eliminates the need for a calculator. First, set the pivot at the edge of the board. Next, rotate the square around that point until the edge of the board aligns with the mark you want on the common scale. Mark a line along the ruled side of the square.

The speed square also makes quick work of hips and valley rafters– same method as for common rafters, but use the Hip-Val” scale.

To scribe parallel lines: An often overlooked feature is the scribe feature. The tool provides a set of notches 1/4 inch apart. Set a pencil in the desired notch and slide the square along the board to mark a parallel line.

Be sure to pick one up before your next DIY woodworking project.