– It's safe to say that if one of your recent projects didn't turn out that well, it's because one or two of these methods were overlooked. So, what methods are we talking about today? Well, we're talking about the two most foundational methods for checking for square. Checking for square simply means checking the faces, edges, and the ends of the boards for squareness. In a bigger sense, it also means checking the squareness of a project, like a picture frame or a cabinet door or even a chest of drawers. Let's begin by learning about the first method, which focuses on making sure that the edges and the ends of the board are square to the face. And the best way to check to see if the edges are square to the face is simply to use a combination square or a precision square to verify it. To do that, pick and mark a face as a reference face, meaning that this is the face that all edges and ends are checked from. And I can't express enough how important it is to always know where your reference face is. That's why I always mark it. Once that the face has been identified, check it for flatness by laying the blade of the square flat on the board. And you'll know that it's flat when you don't see any visible light coming from under the blade of the square. It's also really helpful to hold the piece up to the light or to have it backlit from down below. Next, once the face is confirmed to be flat, check one of the edges and then the other. Again, making sure you're always referencing your square off your reference face. Once the two edges are verified, move on to the end of the board, checking first in this direction and then in this direction. Again, if the edges or the ends are not square to the face, you'll see light coming through the blade of the square just like this. The best way to fix the face or the edge of a board is with a jointer, which is a large power tool that's designed specifically for flattening and squaring edges. And when it comes to fixing the ends of the board, simply recut it with whatever tool you have available, like a hand saw, a power miter saw, or even a shooting board. Because this is a beginner video, I'm assuming that you don't have a jointer, which is the main tool for fixing the majority of these issues. But the good news is that you don't have to own one because you can buy lumber that's called S4S, meaning that it's planned, it's surfaced and smooth on all sides and it's ready to go. However, never assume that what you're buying is always perfect. Do your due diligence and check the faces, edges, and the ends of the board before moving on. That way, if you uncover a problem, you can simply take it right back to the store and get another piece. The second method we're gonna talk about focuses more on making sure that the board or project or sheet good material like plywood is cut and assembled squarely and not cut and assembled like a parallelogram or a rhombus. To better explain those two terms, I made two very basic mock-ups here, first, to help us to learn the terms, and second, to see how these terms apply to our woodworking. The first example is this rectangle, which could represent a sheet of finished plywood or a woodworking project like a cabinet door. For this rectangle to be square, it needs to have two pairs of equal sides. In addition to that, and maybe more importantly, all interior angles would have to be the same, all 90 degrees. Squareness can be confirmed, then, by either a metal square or by verifying that the opposite diagonal measurements are the same. But as soon as I alter its shape like this, it now becomes a parallelogram. And as you can see, it is no longer square. By definition, parallelograms have two pairs of equal sides, and each pair are parallel to each other. Plus, they have two pairs of opposite angles that are the same. Meaning, these two interior angles are the same and these two angles are the same, none of them being 90 degrees. Parallelograms are really common in woodworking and in carpentry. And even in the smallest amount, they can create compounding bigger issues later on for your project. Fortunately, these can be fixed relatively easy, just as long as you catch them early on and before your glue dries. To fix this, look at and verify that you do indeed have two pairs of equal measurements, which simply means you need to go back and recheck all of your measurements. The second thing to do is to see if your diagonal measurements are the same. And here's how you do that. To start, simply measure one diagonal measurement and then the other. Be sure to note the difference between the two and which one is longer. So for example, my first measurement was 14 3/16 or 36 centimeters, while the other one was 14 7/16 or 36.6 centimeters, making this measurement the longer one. The difference then would be 4/16 or six millimeters. Therefore, in order to make this square again, we need to move the top 2/16 or three millimeters this way and the bottom that way by the same amount. Again, if this was a door, you would clamp the long side, which pushes the bottom in this direction, while at the same time moving the top in this direction, which looks like this. Here, let me do it again so you can see exactly what's happening here. Now, once you've made your adjustments, go ahead and remeasure your diagonals to verify that they are now the same. Oftentimes, the clamps are in the way of taking outside diagonal measurements. So you can always use interior measurements as well to check for square. The last thing I wanna talk about before moving on to learn about the rhombus is how to cut plywood squarely. Imagine if our mock-up was now a sheet of plywood that needed cuts somewhere over here. The very first thing that you must check is to see if this edge is 90 degrees to this edge. If it wasn't for some reason, once you pull your measurements from this side to make your mark over here for your cut line, you would essentially be marking out and cutting a parallelogram. And it can be a bit confusing once you finally figure out that something's wrong. Because when you double check your measurements, you will notice that they are the same, which will leave you scratching your head. Bottom line, always check your reference side for square before pulling measurements off of it to make additional cuts. And finally, let's look quickly at the rhombus. The rhombus has all the same characteristics of the parallelogram, but the rhombus has four equal sides. Correcting a rhombus for square is the same as correcting a parallelogram. Double checking that all sides are indeed equal measurements and then measuring diagonals and correcting with diagonal clamping pressure if needed. Now of course, there's a lot more to talk about around these topics, but I think this is a great place to get you started learning the basics. Thanks for watching today. If you have any questions, leave them below. I would love to answer them for you. You can alw
