How to Make Your Own Carpenter Square

A carpenter's square makes repeatable measurements quickly and accurately.

Constructed from steel or aluminum, the carpenter's square is shaped like an "L" and usually features standard and/or metric increments. The carpenter's square comes in various sizes, but the most versatile is 16 inches by 24 inches. Professional-quality carpenter's squares are durable, rigid and often stainless steel or powder-coated to resist oxidation. Carpenter's squares are commonly used to make repeatable, accurate measurements in rough and finish carpentry alike, however, it is also used extensively in roofing, framing and stair building.

Things You'll Need

• Steel sheet metal
• Circular saw
• Metal-cutting circular saw blade
• Hacksaw
• Engraving tool
• Tape measure
• Grease pen
• Emery cloth

Instructions

1. Cut an "L" shape out of steel sheet metal with a circular saw. Cut one leg 16 inches long and 1.5 inches wide, and cut the other leg 24 inches long and 2 inches wide. To ensure the square is a perfect 90 degree angle, draw a triangle exactly 6 inches by 8 inches by 10 inches on the sheet metal. Extend the 6-inch line another 10 inches and extend the 8-inch line another 16 inches to reach the final "L"-shape measurements. Finish the inside corner cut on the "L" with a hacksaw.

2. Smooth cut edges with an emery cloth. Clean excess oil and residue from the carpenter's square with soap and water.

3. Using a tape measure and grease pen, mark out 1/4 inch increments along the inside and outside edges of each leg. If desired, mark out millimeter increments down the center of each leg. Repeat on the other side.

4. Permanently etch each increment line into the steel with an engraving tool.

Tips & Warnings

• Cutting metal generates a lot of heat. Lubricate the circular saw blade teeth with motor oil to prevent overheating.

• Always wear protective eye wear when cutting metal.

References

• Carpentry Pro Framer: Framing Square Basics