Review on Tools Combination Square Metal Body 1794469 by Bob Fasho

A square isn't really a 'square'. It's about 1/8 inch by 10 inches, which is a lot. How do I check a square without access to another square? Here's how: 1) Take a piece of wood with one straight edge, 2) place the base of the square against the edge and draw a line (use your sharpest pencil) perpendicular to the edge 3) turn the square over, lay Hold it against the edge and see if the edge of the ruler is parallel to the line you drew earlier. 4) If the ruler and the line form an angle, then your square is NOT square. You can measure the error by measuring the change in distance from the base to the end of the ruler. Haven't tried it yet, but you might be able to insert the little supports in the slot that hold the ruler in place to make it square. The 6 inch versions are pretty square (I have 3).