Augering through this, so to speak. I am clocking about 30 minutes per mortise at this point, however things sped up a lot when I remembered that I had a 1 1/4-in chisel floating around my tool chest. I also ditched the spur auger and switched to a forstner bit in my 1/2 in drill. I didn’t think you would be able to use a forstner in a hand-held drill. But you can. Here is the base all dry fit and looking ready to go.
Now that the mortises are chopped and the tenons fit, I’m moving to drawbore the joints on the two leg modules. Since the 3/8 dowel stock at the home center is not 3/8 in diameter, I bought 1/2 in rods and pounded them through my home-made dowel plate. I made this out of a scrap piece of 1/4 steel I had lying around. I add a little bit of relief by back drilling with a slightly larger drill after I drill the correct size through the plate.
Here I’m drilling through the plate. I sized the holes in 1/16 increments from 9/16 down to 1/4. I had used the 1/4 before for pegging the breadboard ends of the dutch tool chest. After each hole is drilled, I flipped the plate, used the bit to center the milling machine in the hole, and then swapped out for a larger drill. For the 5/16 hole I used a P drill, which is a little over 0.01 oversize and I kept that general rule for the rest of the holes. The exact dimension probably isn’t import, you just need enough clearance to let the dowel drop through without a lot of effort. I chose the 0.01 oversize because I could easily see the ridge that the drill leaves. Here’s a shot of the ridge after the back drilling (which really isn’t an actual term, but I think it’s pretty descriptive). If you look closely you can see a small ridge in the hole. That gives me the clearance that I’m looking for.
This process is really easy in a bridgeport mill. You can do it in a drill press, just make sure that you have a vise and then shift the vise around to line up the holes. Then lock the vise down to the table and drill on! You have to be careful because the drill will want to grab and pull itself into the hole. You can easily drill all the way through if you’re not on your toes.