Carcass Construction: Friday Update
The roll cabinet is in full swing with plans modified, joinery cut, plywood placed, and assembly underway. It was my sole focus this week as this weekend I will not have an opportunity to work on anything and I wanted to have the case assembled this week so I can move on to the doors.
Before I jump in, I want to address the title of this update. Carcass is not a very nice word. Generally referring to a dead animal’s body, but in the woodworking world a carcass is the skeleton of a cabinet. In the case of my cabinet, it’s the frame and panels, which is pretty much the entire cabinet. The other components of my cabinet include the top, shelves, and doors, all separate pieces which can be removed from the carcass. Now that you have your woodworking fact of the day down, it’s time to move into the activities of the week.
Design Changes
I ran into one snag this week, I cut the side rails to specification and realized they were too short. The rolls would fit, but I forgot my wife also wanted to put a stack of photo books in the cabinet. These books are 14 inches deep, so a rail at 13 1/4 was not quite long enough, if you like doors that close that is.
No problem, I am a woodworker after all and problems are nothing more than challenges to overcome.
I changed my plan. Rather than cutting true tenons I decided to use loose tenons. Loose tenon joinery is where two pieces of wood have matching holes cut in them, then filling those holes is a piece of wood, holding the two pieces together. It is a very strong joint, just like mortise and tenons, and it allowed me to not lose an inch and a half to the tenons cut in the side rails.
Mortises drilled using a router. These are slightly not round which helps keep these rails from spinning.
Floating tenon’s inserted. I used oak, for strength. Plus I had a piece which was close to the right size.
The trick was to make a jig to cut these perfectly. Turns out my jig was not perfect and I ran into a second challenge, but more on that later.
Gettin’ Jiggy
Jigs don’t need to look good, just function.
Jigs are a tool to make your job easier. In many cases, a jig is used to ensure consistency and speed up work. In my case I made a square hole in a piece of plywood. Then I took two pieces of wood and screwed them into the bottom side which were used as fences. I would simply put the jig on the board I wished to cut, plunge my router through the hole and run it around in the jig until the mortise was complete. Rinse and repeat 32 times and it’s done.
The problem came in my fences. They were a little off, like 1/32 or so off. But that meant in my final assembly the boards did not line up exactly, causing them to sit slightly out of square. Enough if I left them it was noticeable, but not enough to impact the pieces.
So I decided to cut the rails slightly thinner, which set them back from the legs and hid the mismatch.
Plywood
A dusty job creating a 1/2 inch wide by 1/2 inch deep groove in solid walnut. This is a dust mask required operation.
Next up, fitting the plywood. I started by dry fitting, no glue, the sides of the case. Then I routed out a groove for the plywood using my router and a rabbeting bit. Once done, I could cut the panels to the exact size of the now opening, which posed a challenge in my tiny shop. Who knew it would be difficult to cut a 4 foot by 8 foot sheet of plywood on a 3 foot by 5 foot table. I have a moment in the video where you’ll see me crawling under the plywood to get to the tools I need, but after a couple of cuts I got it done.
The next plywood step was to create corresponding rabbets in the panels so they will slide them in place. Until I realized the corners were round in my rabbets and the plywood had square corners. Easy enough, I rounded the inside corners of the plywood as you’ll never see them anyway. Now I specifically cut the rabbets so the plywood would be flush on the inside of the cabinet. Originally I wanted there to be a bit of a gap, but I changed that plan when I realized having the plywood flush would make it easier to mount the door hinges. If there’s one thing I’ve learned about woodworking it’s to think ahead and make sure you don’t build yourself into a problem you can’t fix.
The final pieces of 3/4 plywood I needed were for the shelves. Three identical sized pieces make up the upper three shelves. The bottom panel is slightly smaller to fit inside of the bottom rails. The three upper shelves received edge banding, offcuts of walnut from the legs, which is simply glued and taped in place, the tape acts as a clamp. Once the glue is dry I flush the banding up and the shelves are done. I didn’t have a chance to complete these this week, so the shelves are all a next week task.
Pre-Sand
All of my pieces are now fit and complete, for the case at least. I could put the entire thing together now, but it would be a pain to sand this after the fact. So instead I sand now, while everything is flat. I make sure to very lightly sand the plywood as I do not want to sand through the walnut veneer. I only used 220 grit for the plywood for this reason.
After sanding, I final assembled the two sides. It’s much easier to assemble parts at a time. So the sides go together first. After they are dry and won’t slip around on me I will add the pieces that hold these sides together to form the entire carcass.
A Look Ahead
What a busy week. I’m excited to have so much progress done.
Next week I’ll finish sanding, flushing up any areas that need it. Then complete all of the final details I forgot about, do the final assembly of the case, and put the top on.
Then it’s time for the doors. I still need to find some glass for these, so if anyone has a good glass supplier in Portland, leave me a comment. I haven’t ordered it yet because I do not know what size the glass needs to be just yet. I want to make the doors to fit the cabinet first, then I’ll decide exactly how big each glass opening will be.
I’m looking forward to the final stages of this project. I hope you are having fun following along!