Are squares really square?
Have you ever put two squares back to back and discovered that their backs are not parallel? Shining a light between them reveals gaps and off angle inaccuracies? If they are both at 90 degrees, shouldn’t they line up evenly with very little or no light passing between them? That’s what I always thought…
I was reading an article from Fine Woodworking (issue #59) that describes how several manufactures make their squares (Bridge City, Starrett, and Stanley). As it turns out, squares are only guaranteed to be square on the inside “elbow” of the square, not on the outside.
I don’t know about other woodworkers, but I use the outside of the square to set the fences on all my equipment as well as the blades on my band and table saws. I always assumed that both sides were square.
If you want a square that is square on both sides, you have to buy one that is explicitly built and graded that way.
Am I the only one who didn’t know this?
-- Rick -- I never let my lack of talent get in the way of my creativity.