Box joints fingers on an angled corner

[Charles Lent]

You need to make a standard box joint jig, but with a shallow (low) indexing pin and a sloped push block. Then, when you cut the box joints on the ends of your boards, they need to be held at the desired angle. The sloped push block with the correct angle will allow you to hold the board against it's face as you pass it through the saw or router. This angle needs to be 1/2 of the desired angle of the box corner.

Charley