If you are working with plywood, then one thing that you might need to do is to square it.
For most purposes out there, you do of course need perfectly square plywood, which means that both edges are parallel to one another and that the width edges are perpendicular to the long edges, or in other words, all four corners of the piece of plywood should have a perfect 90-degree angle.
If your plywood is not perfectly square, you are going to end up running into big problems.
Are Plywood Sheets Perfectly Square by Default?
Now, most pieces of plywood that you buy should be relatively squared, but with that being said, they’re generally not going to be 100% perfectly squared. When you go to buy your plywood, exactly how accurate the cuts are, does somewhat depend on the source that you are getting your material from.
Some retailers and lumber mills will do a better job at squaring their products than others. Some pieces of plywood may be perfectly squared when you purchase them, but chances are that they aren’t.
You are always better off checking to see exactly how square your pieces of plywood are before you go to use them. This is especially the case if you need your plywood to be perfectly squared, such as for structural purposes. With that being said, most factory plywood will be straight and square enough for most uses.
How to Square a Piece of Plywood
Now that you know that your plywood may not be square enough to use right from the lumber mill, there is a way that you can square yourself. Let’s talk about how to do so.
Step 1: Straightening the First Edge, the Length
Alright, so when you are squaring plywood, the first thing that you need to do is to straighten the first edge. or in other words, make a rip cut to cut the board down to size so that the first edge is perfectly straight. In order to square plywood, you do need at least one of the edges to be perfectly straight.
In order to do this, you are going to want to use a second piece of plywood that is just slightly wider and at least just as long as the main piece that you are squaring. Now, this piece of plywood should have at least one perfectly straight edge. So yes, you do need to have plywood (or a wide board) that is perfectly straight in order to straighten another piece of plywood. You could also use another type of perfectly straight guide.
You are going to set that secondary piece of plywood on your table saw so that the perfectly straight edge rests against the table saw fence. You will then take the primary piece of plywood that you are looking to square and you are going to line it up with that first board that you put on the table saw. You want both boards resting firmly against the table saw fence. You will also want to use some basic wood glue, clamps, or screws to attach both boards together.
Once both boards are attached, you want to turn on the table saw and let it get up to full speed. Using either a push stick or just your hands and being very careful, push both of the boards through the table saw blade. Your primary piece of plywood should now have one perfectly straight edge. On a side note before you start this process you do of course want to ensure that the fence is perfectly parallel to the blade of the table saw. You can now detach the scrap plywood from the main piece.
Step 2: Straighten and Square the other Side
So now that your piece of plywood has one perfectly straight side, squaring the rest of it becomes extremely easy. All you want to do now is to perform a second rip cut on the piece of plywood on the other side that is not perfectly straight yet. All you have to do here is to take that piece of plywood that you just cut, flip it over, and rip cut the other side.
In other words, take the side that you have perfectly straightened in the first step and place it against the fence. Make sure that the fence is perfectly parallel to the blade. With the perfectly straight edge resting against the fence of the table saw, you can now make the cut just as you did in the first step, but here you are no longer going to use that sled that you made in the first step. You should now have a piece of plywood that has two perfectly straight lengths.
Step 3: Make the Cross Cuts
Now that the two long edges of your plywood are perfectly straight, all that is left to do is to ensure that the short edges, or the widths, are also perfectly straight. Remember that you need to have 90-degree angles at all four corners.
Therefore, what you need to do here is to get the miter saw and set the miter to a perfect 90-degree angle so that the fence is perfectly perpendicular to the blade. With the fence set at 90 degrees, place your plywood on the miter saw and then make a miter cut at 90 degrees, or in other words, make a crosscut.
You want to do this for both sides or with edges of the plywood. Once you have made two perfect 90-degree crosscuts on both sides, you should have a perfectly square piece of plywood.
Mistakes to Avoid, Tips & Tricks
With the process out of the way, here are a couple of extra tips to keep in mind to make the process smoother:
- One thing to take note of here is that your plywood may be too wide to use on a miter saw. If this is the case, in order to make those crosscuts, you may need to use a T-square for manual measuring, as well as a circular saw or any other kind of saw that can make straight cuts.
- Of course, when you are using any kind of power tools such as high-speed saws, make sure to wear the proper safety equipment such as hearing protection and eye protection. Also, make sure that you aren’t wearing any long sleeves, or if you are wearing long sleeves, that they are extremely tight on your arms.
Summary
There you have it, folks. As you can see, squaring a piece of plywood is actually rather easy. As long as you have a couple of saws, a bit of common sense, and a few minutes of time, it’s a rather straightforward process indeed.