With a design in mind I bought a couple sheets of 4×8 Birch Plywood and got to work. I don’t have pictures of this part of the process, but the first thing I did was to lay out each piece of the carcass on a 4×8 rectangle in Sketchup so I could get check what’d fit and make sure my grain was all pointing in the right direction (at that point I was thinking I might stain the cabinet). I transferred those measurements to the actual plywood sheets.
When I marked things out, I picked a single edge of the plywood to be my reference. I laid out everything to be either perpendicular or parallel to that edge with a carpenter’s square and a single tape measure for all the dimensions. Then I cut everything to rough size with a circular saw and fine-tuned the sides afterwards with a plywood blade on the table saw. That made sure opposing sides were perfectly parallel and saved me the terror of ripping a 4×8 sheet on a contractor’s saw.
My design called for dado joinery so the next task was to cut 1/4” deep dado’s where I wanted shelves and supports. It went smoothly except for one thing: After finishing all the dado cuts I realized that my plywood varied just a hair in thickness across the sheet, so some of the dado’s were a few hundredths of an inch too narrow. Thankfully I’d set my dado stack based on the narrow end so I didn’t have to “uncut” anything. But, that left me with the challenge of doing a custom-width dado cut for each shelf or settling for sloppy fits.
Now, I figured the odds of me shaving a few hundredths off the edge of a dado – and doing it reliably – were pretty thin. That had me stuck for about a week. I finally decided to set my plunge circular saw to 1/4” depth, line up the rail guide with the edge of each dado, and use the width of the adjoining piece to set it in place at each end & trim the right amount off each dado. THAT was slow work and I’m sure the experienced jocks here could recommend a better way, but it worked.
Finally, after cutting holes for the electrical, I test-fit the carcass with clamps to check how everything fit before the actual glue-up. That was when I found out that my dado set had somehow slipped a bit and cut a few of the dado’s 1/16th or so too shallow. Jeez! I made another trip to the table saw to trim down the adjoining shelves and supports. There was no way I was going to go back & make those dado’s deeper!
Now for the fun part – everything fit nicely so I added pocket holes and glued & screwed everything together. I would have just used glue but the pocket-holes greatly simplified the task of keeping everything lined up and let me start another glue-up as soon as the screws were in place to hold the glue-up I’d just completed. I left the back off for now to make it easier to paint the central chamber. Here’s how it looks – everything is finally nice & square:
The funny-shaped extra hole in the side of the central chamber are to pass through the flexible shaft on my Woodpecker Sidewinder router plate. The shelf part-way up the chamber has a hole in the center for the router and router lift to pass through. My plan is to use that sill to attach sound-deadening and dust collection baffles.
The final fit on the dados was worth the extra time it took:
Thanks for looking.
-- "I'm not afraid of heights. I'm afraid of widths." - Steven Wright