How To Make A Corner Clamp Homemade Machines & Jigs

When you want to make a mitered frame for some reason, like a picture frame, an easy to use corner clamp is a must have. But the problem with most of the less expensive ones you can buy is that they don’t work well. Some don’t work at all, in fact.
So I’ve given this design a lot of thought over the years and finally got around to making it. Unlike most of the ones you can buy, this one puts the clamping force exactly where it’s needed: across the miter, pushing it tightly closed.

This project comes with a free plan and you can get that here:

Corner Clamp Plan

This is the base that’s made from 1/2″ plywood. The slits let the fixed jaws of the clamp to flex inward and clamp the miter together:

Hardware is common and easy to get. Carriage bolts, wing nuts and washers:

I like using plywood, but solid would can also be used to make the jaw parts:

This really couldn’t be simpler – the fixed angled jaws are glued to the base, BUT NOT THIS WAY! I made a mistake while assembling it for the video (distracted by making the video) and fastened the blocks to the wrong side. The counterbored slot needs to be on the bottom, not the top:

Fixed and ready to use and working perfectly:

This will clamp stock up to 3″ wide, but can be made bigger or smaller if needed. I consider this “normal” size, to work with the typical range of widths.

I made a short video showing how I made it: