Clamp a Square so it’s Square
During the last several years I’ve built about 50 wooden try squares for customers, friends and during classes. The most challenging part of the project is clamping the blade and the stock together so they are square.
I have tried three or four clamping strategies – some of them too involved to discuss here. By far, the best way to do it is the simplest.
Here is my procedure:
1. Use hide glue and don’t peg the joint between the stock and blade. If the square gets damaged or goes badly out of square, it’s easier to disassemble the parts and fix the problem than it is to fix the problem on an assembled square.
2. Tape plastic wrap to a known flat surface, such as your workbench.
3. Spread the glue onto the cheeks of the bridle joint in the square’s stock. Push the blade into the bridle joint to smear the glue on all surfaces.
4. Clean off any squeeze-out with a rag and warm water.
5. Place the stock on the plastic with the blade pointing to the ceiling. Clamp the joint gently. Very gently.
6. Put a known square on top of the stock and nestle it into the right angle created by the stock and blade.
7. Tap the blade until it is dead square when compared to your known square. Tighten the clamp a little more. Watch the two squares. Clamp the joint firmly. If the blade moves, loosen the clamp pressure and shift the blade.
8. Remove the “known square.” Walk away. Don’t mess with the clamp or square for several hours.
When I follow the above procedure I usually don’t have to do butkus to square the square. If there is any error, it is usually remedied by removing a shaving or two from the blade.
— Christopher Schwarz
Want plans to build the Roubo try square? You can download the plans for the square here from ShopWoodworking. This is one of my favorite shop tools.