Splined Miter Jig

If you want to build boxes with splined miters, using a jig like this along with your table saw makes the job easy.

The cradle is made of two boards attached at 45 degrees to two outer boards. Your box sits in the jig which rides along the table saw fence while the blade cuts a perfect kerf in each corner. Move the fence to make a second kerf in each corner if you like.

If you use a flat tooth blade, the bottom of the kerf will be flat and your miter key will fit right in. If you use an ATB (alternate top bevel) blade, you'll have a little clean up to do with a chisel in order to flatten the bottom of the kerf so the key fits snugly.

(I had trouble getting clear shots of the blades and yes, I know they desperately need to be cleaned. : )