Combo Squares: The Basics and Beyond
Tips and tricks for getting better joinery from these must-have layout tools
Synopsis: Perhaps the most useful of all layout tools, the combination square is widely used for laying out joinery and checking to see if the corner of a case is square. But it’s also invaluable for diagnosing why a joint won’t come together or close up without gaps, and for checking a joint’s accuracy after it is assembled. Veteran furniture maker Tim Rousseau tells you which combo squares you need and how best to use them to do better work.
Every fall, a new group of students begins the 12-week furniture-making program at the Center for Furniture Craftsmanship in Maine, where I teach. They spend the first few weeks learning to tune and use essential hand tools like chisels, planes, and saws. They also learn about layout tools, and it doesn’t take them long to understand why one layout tool, the combination square, is perhaps the most useful of all. I know I couldn’t work without at least one close to hand.
Many woodworkers understand the fundamental uses for combination squares, such as laying out joinery or checking to see if the corner of a case is square. But they’re good for so much more. I find them invaluable for diagnosing why a joint won’t come together or close up without gaps, and for checking the joint’s accuracy after it is assembled. Here, I’ll help you master this fundamental tool. Once you do, the combination square will help you do better work.
Start with a 6-in. square Combination squares come in a variety of sizes, but the most useful sizes for furniture making are the 4-, 6-, and 12-in. models. Of the three, I use my 6-in. square the most. It’s small enough to fit into joints like mortises and between…