The post the other day about the jig to make them reminded me to go back to my "Tage Frid Teaches Woodworking" and re-visit his dead-simple method.
His first advice is to be sure the size of the fingers harmonises witht he size of the workpiece. So right! If you were to re-create the SOTA TT base a 1/4" finger would look right. Then you would need 2 saw-blades or both outside chippers from a dado set or a 1/4" 2 flute router bit.
All you do is hold a backer piece of 3/4" plywood to the miter gauge and run it through the saw or router to create a 1/4" kerf. Then carefully cut a 1/4" wide piece of scrap that fits tightly in that kerf and sticks out about 1". Now set the workpiece against the jig "finger" and adjust the backer so the next pass you take cuts a kerf a kerf's thickness away.
In actual practice you experiment with test pieces until the backer and the finger it holds give you exactly the right spacing. Then you screw the backer to the miter gauge.
Now you put the kerf you cut at the dge of the workpiece over the finger and run thru the blade. Move over so the finger is in the second kerf and so on. You want to finish so the end kerfs are the same width as the inner kerfs which requires some fooling with sizes.
But it's worth it. And no parts to buy, cranks or whirring gears or micrometers, either.
Easier to show than explain. Wish I could do GPAF but I'm afraid I'll have to PassOver.

• Box Joint Jig