How to Test a Carpenter's Square for Accuracy

When it comes to working with measurement tools, you've got to make sure that they are accurate. Nothing is worse than getting to the end of a project and realizing that your level was slightly off, or your tape measure was crooked. Here are some tips on how you can check your carpenter's square for accuracy.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Carpenter's square
• Pencil
• Piece of wood

1. Place the edge of your carpenter's square against a straight board.

2. Draw a line using your pencil against the blade of the carpenter's square.

3. Flip the carpenter's square over and draw a second line against the first.

4. Remove the carpenter's square from the board and check the two lines. If they appear as one (like they were drawn over each other) then your carpenter's square is accurate. If you see two distinct lines that vary at a given point, then your carpenter's square is bent or curved and needs replacing. Test your carpenter's square before every job.

Tips & Warnings

• To keep your carpenter's square from rusting, spray it with a rust inhibitor.
• After you test your carpenter's square you can adjust it by using a metal punch. Strike it along the corners centerline. Striking it on the outside will move the legs toward each other, while striking it on the inside will move the legs away from each other.
• A carpenter's square is also known as a steel square or a framing square.
• If you don't have a carpenter's square, use a try square instead. A lot of carpenter's prefer it for smaller projects.