The last piece of the cutting board rack design (once I glued and wedged the base together) is to put in a series of dowels which will hold the boards upright. As I said in the introduction, if you change the placement, this would work just dandy for a counter-top plate rack, if you were so inclined.
Boring the holes is fairly straightforward, except that these are blind holes. So, to keep from piercing through to the other side, you must have some way of knowing when your auger bit is deep enough. While you can mark the bit in a variety of ways, from tape to all sorts of whiz-bang contraptions, I find the simplest and most foolproof is simply to count revolutions. The bit feeds at a constant rate, so if 14 full revolutions got you to the depth you wanted, just keep boring your holes 14 revolutions. It won’t slip and has essentially zero setup time. DO REMEMBER that the lead screw precedes the rest of the bit, so make some allowance for it.
Once that’s done, you just cut a bunch of dowels. To keep the ends from splintering, and to keep with the theme I established with the base ends, I tapered off the ends of the dowels. It kind of felt like I was making a miniature palisade.
Glue the dowels into the base, checking to make sure they all go to the same depth.
Finally, after a couple of coats of paint, I put it into the display shelf, and put the cutting boards into it. Now I can fit three boards (54″ length) into only 24″ of shelf space. Much better!