The 2021 CrossFit Open is about to begin on March 11th. They released the equipment list needed to complete the 3 weeks of workouts and on that list is a plyo box. If you are at home working out and feeling handy, I can go through all you will need to build this box.
Difficulty: Easy to Moderate
Bare Minimum tools you will need:
1/8′ and 1/2′ Drill Bit
80-120grit sandpaper and 220grit sandpaper
Materials for building:
(1) 8’x4′ Sheet Plywood*
(1) 2’x6′ Scrap Playwood
1lb of 2′ deck screws
1lb of 11/4′ deck screws
*You may need a little more, depending on how many pieces you want to place inside for bracing. Also, I would buy the better, finished plywood to avoid doing a ton of sanding work later. The cheap stuff will require a lot of sanding and is a bit heavier. Your choice though.
Once you have all of the materials. See if they will cut it at the store to the proper specs. If not, no big deal. I’ll go over how to do it here.
Cut you will need:
(2) 30’x22 1/2′
(3) 18 1/2’x22 1/2′
(2) 13 3/4’x22 1/2′ (Optional – you don’t really need these)
(4) 18 1/2′
Any leftover you can make more braces with and fix them to the edges. I’ll explain where these are going in a bit.
If you are cutting everything yourself with a circular saw, I suggest having a 2×4 handy. Secure the 2×4 to the plywood as a straight edge for the saw. It will be way faster and straighter in the end. Make sure you measure how far you need your straight edge.
Everything is cut. Now what?
Once you have everything cut and measured we can begin the assembly.
Take the 1x2s and fix them to the inside of the 18 1/2 x 22 1/5 Cuts. Make sure they are flush with the edges. These pieces are going on the inside and it’s going to be what the other pieces grab onto.
Once you have those pieces secured. Begin assembling the 30×20 to each side. You’ll need someone or something to hold the walls up with and make sure the edges are flush. If they are a little off it may result in a janky box. Set the corners of the 30×20 and the 20×22 1/2 with the brackets that are in place and pre drill holes along the edge.
*Note: The plywood will split if you do not pre drill the holes. Don’t be lazy.
Once one side is secured together, begin on the other side. Keep assembling the pieces until you have 5 out of 6 in place. You can just set a few screws for now and drill the rest later. At this point we are just trying to get the box shape together before we insert the middle brace. (the other 22 1/2x 18 1/2)
Pre drill Holes along the 30×20 inch side directly in the middle. Measure to the 15′ and mark 3 good spots. That’s where the middle brace is to be secured.
Step 5: Secure the middle brace using the pre drilled holes
Step 6: Assemble the rest of the box and place any may screws as necessary. Like I said, pre drilling the holes will make your life easier.
Step 7: Measure and Drill out handles. This is a personal preference. We did 6′ from the top and 4′ wide 2′ tall. your call on how you want your handles to be.
In order to cut the handles you will need a jigsaw. Drill out a couple of holes in your marked out area. Insert the jigsaw and cut it out.
Step 8: Sand the handles with 120 grit sandpaper and smooth out the edges of the box.
Step 9: If you used cheap splintery wood, sand it with a palm sander using 80-100grit sandpaper. Once you smooth it out a bit, finish it out with the 220grit.
Step 10: Jump on your box!
I hope this helps and you guys have great success with your new box! Please build responsibly. Thanks for reading.