Back in the shop, we’d just finished cutting the joinery for the stretchers. If this were a smaller, modern-style table, we might just stop there and glue everything together. But I look at things a little differently.
Today’s glues will probably be enough to hold everything together. The joints are sturdy enough as it is to hold everything up. But old benches (old everything, really) had their tenons drawbored. It doesn’t matter if your glue is weaker if there’s an oak peg holding everything tightly. So I glue and drawbore in something like this.
I start by boring holes clean through the mortices, about 5/16″ from the edge. Notice that I’ve had to slightly stagger the holes so that they don’t intersect in the leg.
Now, insert the stretcher into the leg. While it’s held up tight, put the auger bit in the hole you just bored and use the lead screw to mark the tenon. When you withdraw the stretcher, you’ll see a little mark in the tenon, but that isn’t where you want to bore. Instead, move it back a little and then bore. It doesn’t take much; in this case I’ve offset it about 1/16″. The mark nearest the shoulder is now where we want to bore the tenon.
Now what’s up with all this nonsense? Can’t we just drill it all out in one operation and call it good?
Yes, you could, but it wouldn’t be as secure. See, the hole in the tenon is offset from the holes in the mortice. This means that the peg is going to have to twist and deform to fit through them all. That force will draw everything together and hold it there. If we had a hole straight through, that force would be absent, and the shoulder line can open up over time. This is more secure, and for a workbench you want all the rigidity you can get.
The last bit of this operation is to cut out some pegs. In theory, you want riven pegs that are then sized using a dowel plate. I haven’t the funds to buy one or the materials to make one. But in this case, you can squeak by without one. If you go to your local big box hardware store, they’ve probably got a bin of oak dowels. Looking through the entire bin for straight grain and no runout, you can usually find one or two that will suffice. I needed some 3/8″ dowels for the stretchers and 1/2″ to join the legs to the slab top. Once I’d cut them to length (leave some room there; I made my about 5″ long to go through a leg 3½” thick), I tapered the ends. You want a fairly gentle taper so that it will snake through the offset holes more easily.
Now the legs and stretchers are ready to be joined together and then to the top. Before we do that, remember that we want a shelf. I used my rebate plane to cut a rebate in all the stretchers so that the boards (which we’ll make later) can sit in there flush. It doesn’t take very long right now. But if you forget until after glue-up, you will not be a happy camper. Next time we’ll put this monstrosity together!