How to Use a Speed Square

In this video, Ask This Old House general contractor Tom Silva demonstrates the amazing versatility of the humble rafter square.

Steps:
1. A Speed Square, also called a rafter square or layout square, has a 90-degree marking edge and a 45-degree marking edge.
2. The square can be used as a straightedge guide when crosscutting with a circular saw.
3. A pivot point allows the square to be used as a protractor for marking angled lines.
4. The square is ideally suited for laying stud locations for walls.
5. Built into the square are several scribing notches, which provide a fast, easy way to mark layout lines or cutlines onto lumber.
6. The perfect 90-degree corner of the Speed Square can be used to determine whether two boards form a precise right angle.
7. To keep the square close at hand, hang it on your tool belt with a hook or get a specially designed Speed Square pouch.
8. You can also custom-make your own Speed Square holder from a PVC baluster.
9. Cut the baluster to length on a miter saw, then cut a stopped slot along one side with a table saw or router.
10. Cut a ¾-inch-thick plywood strip to fit inside the PVC holder, and secure it with short screws.
11. Attach a metal belt clip to the opposite side of the holder.
12. Clip the holder onto your tool belt, then slide the Speed Square into the slot.