How to Build a Cabinet Carcass

April 2021

Building a custom cabinet is a rewarding project that is possible without an expensive tool shop. This post walks through the first step in building your custom cabinet – the carcass. There are three things that when we started this project that I wish my research had enlightened me on:

#01: How to size the carcass.

#02: How to calculate the drawer mount hardware length.

#03: How does the door overhang on hinges impact the door and drawer placement.

Read on to learn our build process, see how we answered the above, and how our cabinet came together:

How to Determine Your Carcass Depth:

#01: Determine the depth of your project: a relatively easy measurement as it is the depth of your space and how the project will relate to the trim – for example, will the cabinet be flush, recessed, or protruding? Make sure to consider how the doors and drawers will look. If the face frame of your cabinet is flush with the back of trim (like ours) then your doors and drawers will protrude from the trim slightly. This is a style choice, but it does impact the depth of the cabinet.

#02: With an established project depth, subtract the depth of your face frame material to get your carcass depth. Face frame material is typically 3/4-inches thick.

How to Determine Your Carcass Width and Height:

#01: The width of your carcass is whatever your project space is provided you can get it into position. For our project, it was the distance between the closet opening and not the inside wall-to-wall distance. The face frame will sit flush on your carcass so no need to count additional width for that.

#02: The height of your carcass is a style choice and influenced by the size and number of drawers that you desire. We wanted our first open shelf in the closet to be 36-inches high, so our carcass height was 34-3/4 inches. The remaining 1-1/4 inches comes from a 3/4-inch base (what the cabinet sets on to get above the carpet) and a 1/2 inch shelf top (the thickness of our plywood) to get a 36-inch total height.

Confident with the knowledge of how to size the carcass, it was time to actually cut some wood.

Time to Build!

1. Cut 3 of your Carcass Panels

It’s time to cut the bottom and the two sides of your cabinet carcass. For this project, we used 3/4-inch cabinet grade plywood (maple) from a big box store. The width of all of these pieces is your face frame thickness (typically 3/4 inches) subtracted from your project depth. Our project depth was 24-inches, so our carcass pieces were 23-1/4 inches wide. I used a handy Kreg edge guide to rip the widths.

TIP: Dado’s were easier to create than I anticipated using a single blade. However, pocket holes and glue also hold together just fine. Put the holes out the “outside” of your carcass and no one will see them once in place and make sure to account for the change in dimensions.

The length of the bottom panel is your project width minus 1/2-inch as there will be dadoes on our side panels. The length (height) of the side panels is the height of your carcass. Remember above in determining carcass depth – this won’t include the top piece or the cabinet base which makes up the total project height.

2. Cut Dadoes on Side Panels

We cut a 1/2-inch dado on each side panel using a single saw blade. We put a sacrificial fence in place so we could rip against the edge when needed. We set the distance from the blade at 1/2-inch and used a test board to get a 1/2-inch depth of cut. We then ran each piece through the saw, adjusted the fence slightly, and repeated. The boards should rest against the fence when being cut. A little sandpaper across the cut area and I had a nice looking dado. It’s faster with a dado stack but can be done without one.

3. Cut Your Cabinet Back Slot

If using a back panel, a 3/8-inch deep groove that is 3/4-inch from the back edge is needed on the bottom and side panels. We used a scrap piece of wood to get our groove depth set. The first cut on all boards is at the 3/4-inch mark. We then moved the fence slightly further away from the board and using our test board ran it through. It looked good, so through the table saw went the three frame pieces. We needed one more ever so slight pass-through to be able to fit the back panel piece

4. Put the Bottom and Side Pieces Together

With the dado grooves, it was easy to align the side pieces to the bottom. Some glue and a few brad nails secured it into place. We used some corner clamps to make sure they finished square to cabinet.

If you’re building cabinets, there are 90 degree clamps that work wonders!

5. Install Support Braces

To bring the cabinet together, you’ll need 4 support braces – we cut 4 pieces from the 3/4-inch cabinet material. The width doesn’t really matter, we picked about 4 inches. The length of these pieces needs to fit nside the cabinet. To attach, we used two pocket screws on each side of the braces. The back panel should be installed before the support braces are installed – we opted not to use the back panel.

6. Cut and Install Face Frame

The face frame sits on the front of your cabinet carcass and shouldn’t overhang the sides. If you’re doing a cabinet only, you could mount the finished top piece on and make the face frame flush with that. We cut the outside face frame and middle (horizontal) pieces to 1-1/2 inches wide. The center vertical column was 2.5 inches wide. The cabinet face frame was connected together using pocket screws and glue. We used an 18-gauge nailer and glue to connect the face frame to the cabinet carcass. Once attached, we ran our sander over everything to make it nice and smooth.

Next up – Time to Install Undermount Drawer Slides

In my opinion, undermount drawer slides are the way to go. They were way easier to install than a prior side mount project. We used Blum 21-inch mounts which were perfect.

See here for a surefire way to install undermount drawer slides with ease!