Tools and supplies I used:

Bandsaw (only attempt this project if you’ve been trained on this)
Router table with ½ inch dovetail router bit (only attempt this project if you’ve been trained on this)
Sander
1 2x6 board douglas fir, at least 4” long
1 2x6 board redwood, at least 4” long

I made it at Techshop: techshop.ws

I inserted the dovetail bit into the router table and adjusted the height of the bit so that it was sticking up about 3/8” above the table surface. I put the adjustable table router fence on top of the normal table saw fence.

Step 1: Making the Female Piece

I moved the fence so that there was about 1” between the top of the bit and the fence, and I noted that the exact position of the fence (on the table saw ruler which is on the front of the table saw/router table) was at 34 1/8”. I placed the douglas fir piece against the fence so that the router would cut with the grain, and I ran the wood through (making a female dovetail). I moved the fence 1/4” further away from the bit (to 33 7/8”) and ran the wood through again, widening the dovetail. I then moved the fence an additional 1 ¾” away from the bit (to 32 1/8”) and ran the wood trough again (making another female dovetail. And finally, I moved the fence another ¼” further away from the bit (to 31 7/8”) and ran the wood through again, widening the 2nd dovetail.

Step 2: Making the Male Piece

I moved the fence back toward the bit and lined the bit up inside the fence opening so that only about half of the bit was sticking out of the fence (to 35 ¼”). I placed the redwood piece against the fence so that the router would cut with the grain, and I ran the wood through. I moved the fence further away from the bit (to 34 5/8”) and ran the wood through again. I then moved the fence 1 ¼” away from the bit (to 33 3/8”) and ran the wood trough again (completing the first male dovetail). I then moved the fence 3/8” further away from the bit (to 33”) and ran the wood through again. I then moved the fence 3/8” further away from the bit (to 32 5/8”) and ran the wood through again. I then moved the fence 1 ¼” away from the bit (to 31 3/8”) and ran the wood trough again (completing the second male dovetail).

Next I removed the excess wood from the far edge of the male piece. I turned the wood around 180 degrees, moved the fence back to 35 ¼” (so that only half the bit was sticking out of the fence) and ran the wood through. Then I moved the fence ¼” away from the bit and ran the wood through again. I kept doing this (moving fence ¼” and running through) until I met up with (and thus eliminated) the 2nd female groove from the previous paragraph. At this point I had the male piece with 2 male dovetails.

Step 3: Fitting the Pieces Together

Next I lined up the male piece with the female piece and tried to fit them together. They didn’t quite fit so I successively positioned the fence to take tiny slices (~1/64") off the front edges of the male dovetails until the pieces fit snugly together but without forcing.

Step 4: Preparing for Final Cuts

Next I measured and drew a square on top of the female piece, centered on the midpoint between the two female dovetails, with each edge of the square at a 45 degree angle to the edges of the female piece (each edge was ~2 ¾” long).

Step 5: Band Saw and Sanding

Keeping the pieced together, I used the band saw (with the miter attachment) to cut along these lines . I then used the sander to sand the outside sides, top, and bottom smooth.