Tom Silva's Speed Square Tricks: Protractor, Layout Gauge, and Scribe in One Tool

The Problem

Most speed squares live their whole lives marking 90s and 45s. The tool was designed as a rafter square, but it carries a protractor, a set of layout gauges, and a scribe — features stamped right on it that most owners have never used.

The Techniques

1. Protractor for any angle. The lipped edge has a pivot point at the corner. Hold the lip tight to the board's edge, swing the square, and read the degree scale — stop at 22½ and your pencil line along the square's edge is 22½ degrees off the board edge.
2. Square stud layout. Marking 16-inch centers, use the square to carry a true square line across the plate at each mark before X-ing the stud side — crooked layout lines become crooked walls.
3. Offset marks for doubles and jacks. Along one edge the square carries marked increments — 1", 1½", 2" from the edge. Marking a jack stud beside a king? Slide the square to the 1½" mark and your line lands exactly one stud-thickness over.
4. Draw a 3½-inch line with the diamond. The diamond cutout sits at 3½ inches — the width of a 2x4. Drop a pencil in the diamond, hold the square's lip tight to the board edge, and drag: a straight line exactly where a flat 2x4 would land.
5. Scribe rip lines with the notches. The square's cutouts hold a pencil at set distances — put the pencil in the notch, slide the square down the board, and you've scribed a parallel rip line at 1", 1½", 2", wherever the notches sit.