I’ve used both 3/4″ oak and birch. I like to finish my boxes with polyurethane and the oak is better for this. If you’re going to paint the boxes, use the birch, which usually costs about 20% less per sheet. I don’t recommend using MDF or particle board. MDF is heavier than hell and particle board isn’t as strong or durable as the other types of wood mentioned above. Both MDF and particle board are susceptible to water damage.
Once you’ve decided on your material, sift through the stack at your local lumber yard or big box hardware store and find the least beat-to-death sheet you can. Then, do yourself a favor and ask the store representative to rip the board into 3 long strips with the heights (20″, 16″ and 12″) of your future boxes (see Diagram 1). Most big box hardware shops will make 2 cuts for free and it makes handing the stock much easier, even for CrossFitters.
In the past, I’ve gotten the tops for the 20″ and 16″ boxes from what’s left of each box’s respective strip. That would leave me scrounging around for a top for the 12″ box.
I haven’t had the chance to try this, but it occurred to me that if you’re willing to pay the extra money (usually about $2) for the store to make a 3rd cut, you could get the top for the 12″ box from the same sheet. Have the store crosscut 17″ to 18″* from one end of the sheet before doing the horizontal rips. This should give you all the stock you need for three tops and twelve sides. See Diagrams 2 and 3.
Note: thanks to Joe Agliozzo for pointing out the original 16″-18″ did not work.
Next week: Cutting the Sides
I intend to treat these ‘how-to’ posts as a living document. So if you have any questions, suggestions or improvements leave a comment or shoot me an email and we’ll modify things as needed.