There is no magic in making quality woodwork projects, it only takes patience and accurate measurements. The patience I am working on, the accurate measurements I rely on others to make quality tools that I purchase and use. Turns out, relying on others to make quality tools is a bit hit and miss. I have three small fixed squares, two inexpensive plastic versions and one steel, brass wood combination (my favorite) I paid over $25 for, and expected that I was purchasing a fine measuring tool ... note that I said "expected" ... click below to see what I really got.
Since part of what I do is making musical instruments, you can understand that I need very accurate measurements ... not close mind you, dead on (hey, I need all the help I can get). To aid me in making these measurements I checked out many good quality squares and finally settled on a nice looking, somewhat expensive brass, steel wood square from Stanley. Every time I used this square, somehow things would go awry. My table saw blades never seemed to be perpendicular to the table, my markings never aligned with my miter gauge, everything seemed off. After struggling for months trying to get my table saw and square to give me accurate cuts, I decided that maybe ... just maybe I should check my square to see if it was as accurate as I had "assumed" when I purchased it. 
To check any square is quite simple I found out (too bad I didn't know this when I was purchasing the square). You simply find a board that has a truly flat edge and lay your square along that edge and draw a fine line, all the away along the perpendicular edge (if you are really picky like me, you could use an Exacto knife blade as a marker). Next, flip the square over and measure the same line with the opposite side of the square. If your square is accurate the second line will follow the first. If your square is off, the second line will show you how far off it is from the original line.
I found an old piece of white shelving with a dead flat surface to check all my squares with. When I checked my favorite, the Stanley square, I was astounded to see how far off it was. In fact I had to test it three times before resigning myself to the fact it is not even close. No wonder I couldn't get accurate cuts, I had been fighting a faulty tool all this time.
Next I selected the plastic square I won as a door prize at a woodworking meeting. The ticket cost me $5 and I noticed the price on the square when I picked it up was $4.95 so I was even as far as cost went. Surprisingly the yellow Swanson square was far more accurate than my $25 Stanley square.
Next last one I tried just on a "lark" it's old gray square I picked up at a flea market and doesn't even have a brand name on it. I had paid a whopping $3.50 what a deal. Now came the real challenge, would it be any more accurate than the two more expensive squares. I am almost embarrassed to say ... it was dead on accurate. The Stanley was the worst, it was off by over 1/16th, the Swanson was off only slightly, maybe 1/64th and the grey non-name, if it is off, it was undetectable.
So ... now you can check your own squares for accuracy and don't assume your most expensive is accurate ... mine sure isn't.
Editor's Note: Unfortunately the detail of the lines cannot be seen as clearly as we would like in this image but one can still appreciate the differences.
The only squares I have that I can rely on ALL THE TIME are my Engineer squares that I use for setting up fences and blades. These are excellent squares and will serve you with accurate setups the rest of your life!!!.
Copyright - Colin Knecht
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