When you’re building boxes out of plywood, it’s always good to use clamping blocks to keep things square. These DIY clamping blocks are actually multipurpose. You can use them as corner clips to hold your boards in place at a 90 degree angle while you nail them together, and since they have parallel surfaces you can easily use a bar clamp to pull your boxes back to square while the glue dries if need be.

Making these DIY clamping blocks is easy and in expensive too. Use a scrap piece of 2×4 anywhere from 4 to 8″ in length. The longer the piece the more the pressure is dispersed along the length of the plywood. Cut two 45° angles on one end in order to make a point. Then use a dado blade on your table saw, or a straight cutting router bit, to make two dados 3/4″ deep. One of these dados should be going along the length of the 2×4, while the other dado is going perpendicular to the first. Make certain these two dados are cut at exactly 90 degrees! You’ll also want your shorter dado to be about 1″ from the point (or less).

It should only take you a few minutes to make a pair of these DIY clamping blocks. And it makes sense to have a pair (or two) for each width of plywood you use in your shop.

* This post may have affiliate links, which means I may receive commissions if you choose to purchase through links I provide (at no extra cost to you). As an Amazon Associate I earn from qualifying purchases. Thank you for supporting the work I put into this site.