How to cut box joints with a box-joint jig
Cut evenly spaced fingers and slots on a dado stack, indexing every slot off the box-joint jig's key.
Chapters
How to build one: Box-joint jig
A box-joint jig stands the board on end over a dado stack. Its key, one finger wide, sits one finger from the blade, so each slot you cut drops over the key to place the next.
Transcript
0:03 The jig stands the board on end over a half inch dado stack, its key a finger from the blade. This board starts with a finger, so push it to the key.
0:15 Lift the board, drop the slot you just cut over the key, and cut the next. The key spaces every slot a finger apart.
0:29 Step across the board the same way to the last slot.
0:42 The mating board starts with a slot at its edge. Put a half inch spacer between the key and the board for its first cut, then take it away.
0:52 From there the key does the indexing, just as before.
1:05 Each slot drops over the key for the next.
1:18 The last slot finishes the board, and its fingers fit the first board's slots.