The humble box is the most versatile thing you’ll ever make. And it’s ever so simple. But there’s still room for error, and trust me, there’s nothing worse than putting the time and effort into making something that turns out wonky! I am by no means an expert on building techniques, but I did do a little online research on building a square box and have learnt quite a bit through trial and error. I’d like to share my thoughts and tips with you!
These tips are for building a box where there is no frame; it is just nailed together at the sides. Boxes without frames are quicker and easier to make, and come out lighter and more slimline. Of course, if you’re building a massive box, or you plan to be using it to support something really heavy, you’d build a frame and then clad it. For most other projects, a frameless box would be fine 🙂
To build a square box, you have to “check for square” every single time you put pieces together that form a square (sounds pretty straightforward…) This includes as you build a side, and as you put sides together to build a box.
How to check for square?
There are lots of fancy rulers and gadgets out there, but I haven’t bothered buying them yet; I have found a long (120cm), good quality metal ruler to be good enough. I have also found my right-angle ruler to come in handy. When you nail 4 pieces of wood together to make a square, the 2 diagonals need to be the same length. It’s as simple as that! If you put one nail in each corner, you will see that it’s easy to move it out of square, into more of a parallelogram:
I’ve circled the bottom right corner because it’s the most obvious (but of course, all corners are wonky!) You can see that the corner is not at right angles – the angle between the two pieces is less than 90 degrees, and the piece on top is ‘skewed’ on the pieces it is sitting on; the bottom edge isn’t lined up. If you were to measure the diagonals from outside corner to outside corner –
– the diagonal running from top left to bottom right would be longer than the diagonal running from top right to bottom left.
This is easy to fix when there is only one nail in each corner! Just grab the top left and bottom right corners and push them toward each other. Re-measure and push/pull until diagonals are equal. Then, put a second nail in each corner to keep it square.
If you don’t have a nail gun, I recommend pre-drilling before nailing or screwing so that your pieces are less likely to move as you’re attaching them.
The square diagram above is going to form one side of your box, so next, you need to fill in the rest of the side with additional slats, and repeat the process so that you have 2 sides.
So that we don’t get confused about what “side” we’re talking about, pretend you’re making a shelf – i.e. a box that is turned on it’s side, with the opening at the front. The two sides you have just made will be the left and right sides as you look at the shelf from the front.
The top and bottom sides don’t have a support piece (yellow in the pic above) – they get nailed directly onto the left and right sides:
You need to check for square as you do this. I find the easiest way is to stand the left and right sides up, then nail the edge piece on like this, using one nail in each corner only:
If your side pieces won’t stand up, you can clamp the other edge piece on to the top.
Then, carefully, pick up the whole unit and put in on the ground, right side up. Rest your other edge piece on top, and check for square:
Once you’ve found square, put 2 nails into each corner and fill in the rest of the side with extra slats.
I have found it easier to make the box square by adding on the back next, rather than the bottom. If you were to add on the bottom next, you’d have a 3D cube without a front or a back, which could have a tendency to be pushed to a 3D parallelogram. Nail on the edge pieces and check for square. Then add the middle pieces.
Repeat this for the 5th & final side (the bottom of the shelf). You should end up with a beautifully square cube!
I hope you found this useful!