When timber framing, all of the joints must be cut before the whole structure is assembled. That’s because the structure is usually too big for assembly to be done in stages. Another reason is that it’s hard to lay out and cut joints on workpieces that are already attached to other pieces. The bunk beds I’m building are just small enough that I can assemble everything in two stages, but even that is cumbersome work. All the joints must still be cut before any assembly is done.
Working on one side of my dining room usually affords me enough space for my projects, but not this time. I had to move the dining table and just about everything else in order to lay out the lapped dovetails for the side rails.
I cut the large dovetails (condor tails?) with my rip saw and panel saw, each tail requiring six separate cuts. The mortises for the tails took some ingenuity to excavate.
I began by boring wide, shallow holes across the end, then squaring up the corners with a chisel. Next, I used a stair saw to cut the walls of the mortise. Finally, I used a chisel and router plane to remove the remaining waste.
My wife offered to help excavate the mortises. That was indeed a help, as there were 26 to do.
When all the joints were cut, I glued up the end assemblies. Finally!
Pipe clamps are wonderful things. Using 36″ extensions, I was able to clamp the entire assembly using six clamps. On the assembly shown, there are shelves as well as end rails. I glued it up without the shelves and, after the glue had set, I slid the shelves into their dadoes and glued them in as well. Each bed will have two shelves. The other assembly was simpler, having only six rails and no shelves to deal with.
The pieces assembled easily because I intentionally cut the joints fairly loose. As one old timber framer liked to say, you should be able to knock the pieces together with your hat.
I’m a novice timber framer, so I had to use a mallet instead of my hat, but they went together easily enough.
The strength of the assembly does not come from perfectly mating surfaces glued together. Rather, the structure’s integrity relies on the mechanical strength of each joint. After assembling the mortise & tenon joints in the end assemblies, I drove oak wedges into each tenon to wedge the joint. It couldn’t come apart even if it weren’t glued.
I asked my oldest daughter if it looked like I was making progress. She said yes, it did, but it still didn’t look much like bunk beds.