With the hard part of the project done, it was time to finally make this beast into a frame. There was another jig I needed to make: a miter sled. I used the principle many have used before me: it’s easier to make a perfect 90 degree cut than to make 2 perfect 45 degree cuts. A couple pieces of plywood later (and hardwood runners) I had a very useful sled that will come in very handy around the shop.
Quick check that everything matches up – perfect!
Because this frame is very large, I wanted sturdy joinery. I opted to use hardwood splines, which meant another jig. I made a simple tenoning-type jig that rides along the table saw fence. Another jig that will come in handy on future projects.
I started by glueing the splines into one side of each joint.
Then the final glue-up. It didn’t go quite as well as anticipated, but I managed to get everything together and close up most of the gaps. I didn’t worry too much since this will eventually painted – those gaps can be filled.
A little flush routing and sanding cleaned the splines right up.
I was extremely pleased to find that the whole frame sat flat on my table saw surface – no warping or twist at all!