Knowing how to make a simple box frame out of 2x4 is one of the most basic yet useful skills you can have.
Although you can build a box frame by simply screwing into the end grain, that results in a very weak box frame.
Instead, a better way is to use pocket hole screws to join wood at 90°.
For this, you'll need a pocket-hole jig.
The one by Kreg is highly popular and that's the one I'll be using in this guide.
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Things You'll Need
- Kreg Pockethole Jig
- 2x4 wood
Making the Box Frame out of 2x4
The box frame can be of any size you need.
So I'll be focusing on the joints and the process instead of the size of the box.
Place the 2x4 lumber on the work surface.
As the first step you need to determine the size of the box frame you need.
All the 2x4 pieces with the same number should have the same length.
So you'll need to make 4 pieces of each length.
The actual length you use for these pieces depends on the size of the box frame you need.
The best way to size the 2x4's to the required length is using a miter saw.
Take the 2x4 lumber, place it on the miter saw and make four pieces of each length.
Once you have the pieces ready, it's time to make the pocket holes in each of the pieces.
For each corner where three pieces join, you need a pair of pocket holes in two of the pieces.
So the next step is to make pocket holes as per this plan above.
I'll be making pocket holes at both ends of all the pieces marked as 1 and 3 in the plan above.
To join two 2x4 lumber together you need to use 2-½" pocket hole screws.
First set the pocket hole jig to the setting for a 2-½" screw.
Drill pocket holes at both ends of each of the appropriate wood pieces.
Next, you need to use the 2-½" screws and join them one by one.
First, you need to make the bottom square.
For this join each corner of the bottom rectangle using 2-½" screws and an impact driver.
You can either hold the piece in place while you join it, or use a right angle clamp from Kreg to keep it in place temporarily.
Join all the four 2x4 pieces of the bottom rectangle in this way.
Make the top rectangle as well in the same way.
Next, you need to attach the vertical pieces to it.
Take a vertical 2x4 piece (no. 3) and join it to one corner of the bottom square.
Hold it in place with your hand or use a right-angle clamp.
Join the other three vertical pieces as well in the same way.
Next, you need to join the top rectangle to the rest of the frame.
For this, rotate the frame by 90°.
This will help you join the top rectangle easily with the additional support of the work table.
Align the top rectangle with the appropriate pocket hole location and join with pocket hole screws.
After this, take off the clamp on the other end and join using pocket hole screws just like on the other side.
With that, you have completed making a box frame out of 2x4s.
You can choose to make any box frame with the size you want using this method.
Although it might appear tedious compared to just screwing into the end grain, it's much stronger to use pocket hole screws instead.