This bench's base is assembled using 2 side assemblies connected together using front/rear stretchers with barrel bolts. I thought drawboring the side assemblies was appropriate. I used 3/8" oak dowel stock with a 3/32" offset. Once the the holes were bored, I used the same brad point bit to mark the center point of the the holes in the mortise cheeks.
With the side assemblies glued and drawbored, I had to figure out an accurate way to drill the bolt holes for the stretchers. I decide to do this in 2 steps: drill a whole in the center of the mortise from the inside out, and then dry assemble the base and use that hole to drill into the tenon.
For some things nothing beats a bit and brace, if you don't believe me try it. You will be surprised at how accurately and cleanly this wheaties powered device will bore holes. Keep a square handy, to make sure your sense of square is true.
With that I bored the holes for the barrel nuts, got the ratchet out and cranked these bolts home.
This base is stout, heavy and I can't wait to mount the split top to it.