They're also devilishly difficult to make. The 45 degree angles need to be cut dead-on to avoid gaps, and the gluing-up process is a horrorshow- the moment you clamp a miter-joint-to-be, the pieces slide around.
Various companies sell a host of jigs and tools for easing the problem. But here's a method that has worked quite well for me, using nothing beyond normal shop tools.
What you'll need:
- 4 mitered pieces to glue up. You may be able to adapt this process to work on individual joints, but here I'll only talk about gluing up a rectangle all at once.
- A table saw, with a sliding rip fence.
- a decently straight board, long enough to clamp at both ends of the table.
This Instructable was made at Xerocraft, the Tucson Hackerspace, and is intended to count towards our sponsorship from Instructables.
Step 1: Set up your fences
Now, you can move the fence anywhere else, and it will be parallel to the wood straightedge.
Slide the fence away, and lock it down the exact width (or slightly closer) than the width of one side of your rectangle. With a piece of soft pine as a fence like what I've got here, I can set the gap slightly smaller, and the miter pieces will just stick when they're perpendicular.