Miter joints are probably the most common joint used to make picture frames, and they are popular for cabinet doors too, but they aren’t that easy to get traditional clamps on. I’ve seen a lot of ways to clamp miter joints- the corners usually tend to slide around with traditional clamps because the pressure isn’t delivered squarely across the joint, so it’s a pain to get them all lined up.

This method that I learned from Lance Patterson is my go-to for miter joints- it just works great and doesn’t require any fancy gear- all you need is some heavy weight string and a bunch of square wooden blocks- I used some mason’s twine (cotton string holds a knot better, but it’s what I had…) and made a bunch of 3/4-in. square blocks from some scraps of frame material.

This “string and block” method also naturally holds the corners together in the proper alignment, which makes your work a lot easier once you put the glue on and the clock starts ticking…

Using this technique is pretty straightforward. I cut the miters and smoothed the machine marks on the inner surfaces of the frame with a card scraper and sandpaper, leaving the smoothing on the outer edges for after the glue up. Next I got out my string and cut a piece that would wrap all the way around the frame, with about a foot extra to make it easy to tie a knot.

Tie the string in a loop that’s just a little smaller than the frame- I use a square knot- it needs to hold without slipping, but keep that in mind you may have to undo it a few times to get the right fit. The string should stretch tight when you put it on the frame.

Next I glued each corner and put the string on, and checked to make sure each corner was even and flat, then started working my way around popping the blocks under the string on each side one at a time, then added a second block to each side the second time around.

Once all the blocks were in, I slid them towards the corners, which increases the clamping pressure on the whole frame, and also directs the pressure directly across the miter joints, to pull them closed tightly. Then it was time for dinner, so I set the whole thing aside so the glue could dry overnight.

The next day I added the splines. I took the string and blocks off of the frame and started setting up to cut the mortise for the splines with a stopped-cut on the tablesaw. After using a square to lay out a spline on the frame, I raised the blade until it would cut a near- 45 degree mortise into my frame. I marked where the cut would start on the throat plate of the saw, and cut to my marks on the frames.

Since the tablesaw blade made a mortise about 1/8-in. wide, I milled the splines to fit them, using a nice dark-colored wood from the scrap bin to contrast with the cherry frame, and glued them in. After that, the corners just needed a quick trim of the splines and some sanding to clean them up. The most time-consuming part of the job was letting glue dry- I think I spent about $5 on string, and now I have a new custom-made picture frame for the baby’s room.

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