I cut dados in the top and bottom pieces and along the front and back of all four sides (to receive bracing). Dados make assembly so easy - no nails or screws, just Titebond II wood glue. Bessey K body clamps are a wonderful piece of engineering.
Before I nailed the braces in I pulled them tight to the corner with a clamp. That forced the warped plywood flat and made the corners square.
The pocket holes don't have any function in these boxes. The braces were cut out of left over scraps from my oak coffered ceiling project.
More bracing. I installed four more sticks to brace the middle of the panels. I cut the ends at a 3 degree angle so I could tap the sticks into place without bowing the panels out. I didn't nail the ends but the braces are nailed together at the intersection. I've got gobs of glue everywhere.
Rough sanding of the rabbit joints.
True up the edges where the front and rear baffles go. (mostly clean up glue squeeze out).
Do a round-over on the corners.
Fabricate baffles - I have a sheet of Chinese birch plywood for baffles.
Are you going to stuff your cabs with polyfill?
What's the general consensus about stuffing? I've heard it makes the cabinet model slightly larger. Any other audible effects? This is my first speaker construction project so any suggestions are welcome.
Depending on how much power you're giving each, and how hard you're driving them, AIUI, stuffing a pillow or two in each will help with efficiency, but might make you reach xmax a little sooner (higher up in frequency).
I think I'll run them unstuffed to start. I'm not going to do any wood finishes right away - can always stuff later when I take the drivers out to finish the cabs.
OCD on display. I kept adding sticks until the "rap test" gave a consistent sound everywhere. I'll calculate internal volume now that the bracing is in place.