How Square is Your Square?
Try this simple test to check the squareness of your square.
Feb 16, 2016
https://youtube.com/watch?v=YTwweKrjvTM%3Frel%3D0
There are many self-imposed barriers to woodworking. It is easy for someone just getting into the craft to become frozen with fear over any number of things that with experience seem silly. Here is a very embarrassing list of mostly trivial things that I got hung up on when I was starting out as a woodworker.
• Is my square really square? If it isn’t, everything I build is doomed to be crooked and ugly.
• I need to make everything out of poplar because it is the state tree of Tennessee. (really!)
• I can’t possibly stain or paint my work, even though I want to use poplar.
• Plywood is all I can afford to build a project, but fine furniture never uses plywood.
• Every piece I make (including the first one) must be fought over by my children and my children’s children for generations.
• Freehand sharpening is the purest form of sharpening and anything else is evil.
• Anything short of absolute consistency and precision when sharpening is unacceptable.
• No metal. Never ever use any metal fasteners.
• I must design everything I make.
Obviously, I’m kind of weird and many times I had contradictory beliefs. Looking back at this list, I see someone who had way too much time on his hands and way too many ideals. I wish I could tell my new woodworker-self that it would take years before I made something I liked in spite of its flaws. The only way to get the bad projects out of your system is to build them. Some people are more naturally gifted than others, but you need to build your way out of that hole.
I want to dispel as many myths for the beginner as I can. For starters, I spent sleepless nights worrying about how true my square was and I thought that the only way to fix that particular problem was to throw money at it and buy a Starrett. You’ll see in this video that’s not the case at all. The most expensive squares aren’t the only ones that are true and sometimes, the most expensive squares aren’t even the truest.
Comments
I just got an email that comments weren't working on this post. Apologies. Obviously fixed now.
Love the format of your video. Informative, creative and fun all at the same time!
Well done.
Awesome!
Whilst the theory is correct I disagree that this can actually tell you if your square is correct or not. Not using an offcut of MDF anyway. I'm sure that some makers of high end squares will be overjoyed to find that they are being told their measuring equipment isn't correct because it does not line up with a bit of home cut wood.
Firstly, how do you know if the bit of wood is flat and true? It would be impossible to achieve this at home no matter what you tried. Any curve or dip however slight would set the line off. It could be that in this test video the board was not 100% flat and the best result came from the worst square because it compensated for the edge of the wood.
The reality is that there is only one way guaranteed to ensure that you are using a tool known to be square in the first place. In other words an engineering square with a calibration certificate. Probably way too far to go in a home workshop but buy a half decent engineers square and use that as a reference too. If you want to use the idea in the video then use an engineers square first to determine that the board used isn't going to give you a false reading.
chiefengineer - I think you're missing the overall point of the video. Sure, there is always a more precise way of measuring any tool but the point is to show how to get a good read of how accurate a square is and the fact that you can get a good square for not a lot of money.
Settle down, Francis.
Here's a tip.... Test the edge your using with a straight edge to make sure it's true. Flipping along a misaligned surface can introduce errors and make everything look bad. If you own an adjustable square that isn't true you can modify it to bring it into true with a file. Be sure to only remove small amounts at a time. I have many squares from flea markets that have been adjusted to be true and dependable. Enjoyed the format. Maybe next time leave out the brand names. Maybe just show cost. Most companies work hard to justify their higher price and for the most part "you really only get what you pay for". Especially with Starrett. For the hobbyist or professional measuring and cutting straight lines is extremely important.
Nobody is perfect so it is perfectly fine to make mistakes in your projects especially your initial ones which you have just started to work on. Regardless of how crooked or imperfect your masterpieces turn out to be, take those experiences as a motivational stepping stone for you to strive even harder for future projects by not repeating those same mistakes.
Your test seems like a simple one but if you move the pencil a little differently for each square you could get different results. After many years of drafting, this can be easily overlooked.
There's a simple method to test whether your results are meaningful, repeat the test on another piece or a different part of the edge. If the results are consistent, you're all set. If not, you need a better test piece. Also, keep the test line pairs close to each other so you're using the same part of the edge for the test.
I have a granite surface plate that I use for sharpening. It's also ideal for doing this type of test, since it's ground to extremely high tolerances I just tape a piece of paper to it.Some machines have ground edges on their tables that make them suitable, too. The track for a track saw could even be used. There are plenty of options for testing if you look for them, though you may not be able to bring them to the store with you.
Great job Ben! While the message is clear and the advice is welcome, the medium of your video is also entertaining. Thanks for making it fun! Looking forward to more great tips and your videos.
Mr. Strano has proven that using test methods that are as close to a joke as possible to prove that Starrett tools have misled their users, tool and die makers as well as machinists by publishing inaccurate standards for their combination squares because they don't work on seemingly straight pieces of MDF. You can send me your now useless Starrett combination square based on your findings and Ill straighten it out.
Looks like a very handy tool, it's also cheap which makes it really affordable and worth buying ...
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