Who are we supposed to believe???

Gotta measure to a reference line.
Take a known straight edge – and place the square on it and draw a line. then flip your square over using the same edge and draw a line beside the first one.
IF they are parallel you are good – if not – the square is off.
I have always seen how to straighten carpenters squares – but on adjustable squares – I have no idea how to fix them.
Here is the engineer/geek in me – I would bring a nice staight piece like 12×6 MDF to the store along with a pencil and “sort” through the squares and find one that is nuts on.
For precision – use an exacto line and see if you can scribe a perfect match. As for your collection, go through them and figure out which one is “Right” – and send the others to a garage sale – so you don’t accidentally set up machines using them.
Good Luck
Dave

-- Its never too late to have a happy childhood. But the second one is up to you and no one else.

like Dave suggested, it’s fairly simple to check a comb. (or regular) square for squareness.. you don’t need a secondary ruler to check against.

place your square against a straight edge, and draw a line- flip the square, and draw another line at the same location- if the lines align in one another -your square is good to go, if it’s off square, you’ll notice the error in the angle between the lines.

-- When in doubt - There is no doubt - Go the safer route.

Well that’s along the same line as Dave but I’d take a framing square or other square and put it along a straight edge of wood draw a line flip it to the other direction to test if it’s square or not . if it’s square it will match the first line if not there are ways to correct it but to solve this problem keep testing your squares until they pass this test them compare your other squares the same way,

-- Jim from Heirloom Woodshop Southern Oregon

I’d say stick with the accurate square/squares, and sell or give the others away. There’s nothing worse than having tools that aren’t good at what they are designed for.

-- Julian, Park Forest, IL

Don’t forget an architectural drafting triangle is another good source for checking for square and I agree with everyone else about about getting rid of the out of square squares.

-- criticism: the art of analyzing and evaluating the quality of a artistic work...

Perhaps there’s some “out of kilter” universe where all these things belong that I should send it to…a twilight zone for measuring devices. -SST

-- Accuracy is not in your power tool, it's in you

I think you have probably learned how to determine whether or not your squares are accurate. What I would like to suggest if that if your squares are all so out of whack – maybe you are not treating them like precision measuring equipment.

I have a couple that I treat with the greatest of respect. I used to have three but I dropped one on the concrete floor in the shop. It is no longer a precision devise.

I suggest you get yourself a new set of good squares and don’t drop them.

The best square I have is probably as old as I am. It is a steel framing square that came to me from my grand father who was NOT a woodworker. The only things I don’t like about it are two. One – it is heavy and two – it is dark in color and hard to read. I can’t bring myself to clean and polish it. It came this way and that just doesn’t seem right. Crazy, I know.

-- Making Sawdust Safely

I agree.. I have a starrett that I bought years ago and use it quite often and after I’m finished with it.. back in the box it goes and get’s put away..I have made it clear to others in the shop to please do not handle it since it was very expensive and I use it for precision measurments. you have to have a good precise measuring tool.. I also have a stainless steel ruler that has the increments etched on it that I use solely for layout..the ol tape measure stays in the toolbox when I make furniture..LOL

-- Randall Child

tom…my students called me square…and i asked them if they were sure…and by what measure?

-- Matt, Napa, CA...fun is beautiful...just trying to have some fun...

You can buy a reference square from Edward J. Bennett Co..

-- Joe

the law of averages exists in a square?

if you own enough squares, and measure and mark them, an average develops….........generally to your favour providing the squares you own are indeed “square”...............and then any fool can say what he wants?

if you own just one square…...................just not much of an average?

I guess the key is to be able to make the “un-square square”......square?

does any one know how to do that?.......................or do you all go out and buy another square that isnt square?............and then how do you check if its square??????

-- http://www.furnituremann.ca/

answer

make sure the outside edge of the square fits the door you just made so that not even a sliver of light comes through when held to the light and when all hell breaks loose, blame the square maker?

?

-- http://www.furnituremann.ca/

Dave got to the square root of squaring squares right off the bat. That’s how I check my squares for square. I haven’t had any unsquare squares of the squares I’ve checked for square. My framing square is square and I use that square to square my other squares. I was thinking about to resquare the square of my trisquare when I was checking it, but it was still square even when loose and sliding, so I didn’t have to resquare that square afterall.

I think checking a square for square is at least to the 4th and bringing in another square to square it would be a square of at least the 8th. As far as gettinig to the square root of squaring squares, this is as close as we will ever come unless we digitize the issue with a Wixey, but then are we checking the square or the Wixey?

-- Debt is nothing more than the 21st Century's form of slavery.

You can buy a reference square from Edward J. Bennett Co..

From the guy who brought you “Overly complicating Table saw alignment” comes “Overly complicating tool checks”

Finally…some tongue-in-cheek. I was beginning to think I had lost my touch.

And, by the way, none of my squares have been dropped or abused in my (considerable) lifetime, nor do they show any signs of that from previous lifetimes…and, like I said, all my projects fit together. (Although maybe I just clamp the stuff hard enough to squish the stuff together. -SST

And remember…cupcakes may be round, but pie are square.

-- Accuracy is not in your power tool, it's in you

3 4 5

A B C

Pythagoras was never wrong, except for commas.

-- I am the man in the arena. Q-Woodworks

Go to your local Staples or OfficeMax and buy a large plastic drafting triangle. They are surprisingly accurate and can be used as reference squares.

-- The days are long and the years are short...