Flush-Fit Cabinet Doors
A SIMPLE JIG FOR A PERFECT FIT
Flush-fit or inset doors are found in a wide variety of furniture styles from Philadelphia highboys, to Shaker cupboards, to sleek contemporary pieces. The greatest challenge in hanging a flush-fit door is achieving an even gap
between the doors and the cabinet while accurately locating the mortises for the hinges. After all, there are no adjustment screws on butt hinges and there’s no door lip to cover the cabinet opening.
The good news is that a few savvy techniques and a nifty jig will have you hanging these doors like a pro. I’ll show you how to achieve the perfect fit every time. We’ll even cover fixing goof-ups.
Fit the Cabinet Hinges First
First things first. Whether you’re making a cabinet with a face frame or one without, cut the mortises for the hinge leaves in the frame or case sides before assembly. This saves hassles later when rails or cabinet tops can get in the way. I use the same technique for mortising the case as I do for the doors.
Make the Doors
I always dimension my doors so they are the exact size of my case opening. This approach lets me fine-tune the fit of the doors to the cabinet once it’s built.
Flat and square doors prevent untold headaches later. Be sure to work on a flat surface when you glue up your doors, and center the clamping pressure over the joints. Before the glue sets, check each door for square by measuring its diagonals.
Trim the Door to Fit the Case
At first the doors won’t fit into the case opening because there’s no gap. That’s OK. This two-step trimming procedure allows you to get the perfect fit:
The first step is to joint all four edges of each door. Periodically check the fit,.and joint until you have a gap of roughly 1/16 in. all around between the door and the case.
The second step is to fine-tune the fit of the doors to the case. Position each door into the case on a pair of shop-made hangers.
Shop-made door hangers hold the doors in place so you can scribe for a perfect fit. They’re constructed from two blocks of hardwood and a metal tie plate. Tie plates are used to join house framing and are available from home centers.
First, trim the edges on the jointer. Set the infeed table for a light cut (1/32 in. or less), and joint all four edges. A scrap block steadies the door and prevents end-grain tearout.
Position the doors on hangers and check the fit of the doors to the case. The hangers hold the doors flush with the cabinet face and establish a 1/6-in. gap. Set the compass to the largest gap, then mark around the doors with the compass.
Chances are, your doors won’t fit the opening with precise, even gaps all around. To make the gaps perfect, use a compass to mark the doors (Photo 3). The hangers prevent the compass from scribing across the entire width of the door, so use a straightedge to finish.
Next, clamp the door in a bench vise and trim to your marks with a hand plane. For paired doors, plane a slight back bevel on the stiles where they meet.
Installing the Hinges
Position the doors back into the case and mark the locations of each hinge mortise with a sharp knife.
Back at the bench, square your knife marks across the edge of the stile with a square and a sharp pencil. Set a marking gauge to the desired width of the hinge (Photo 6). Then mark the long-grain shoulder of the mortise.
A router makes for fast, accurate work when cutting mortises. I use a 1/4-in. straight bit to cut all my hinge mortises because the smaller diameter lets me get very close to the inside corners of the mortise. Set the height of the bit to the thickness of a hinge leaf.
Clamp the door firmly in a bench vise and secure a scrap board to the benchtop. The scrap board’s surface must be flush with the edge of the door to support the router base. Now rout the mortise freehand.
Plane the edges to your compass marks to true the doors. Use a sharp bench plane set for a light cut. Maintain a square edge by checking your cuts with a square.
Mark for hinges by positioning the door into the opening with the door hangers. With the hinge stile tight against the case, transfer the shoulder locations of each hinge mortise with a sharp marking knife.
How deep should you install butt hinges into a door and case? The rule of thumb is to measure from the center point of the hinge barrel to the outside edge of one leaf, then subtract about 1/16 in. This layout ensures that the door won’t bind on the face of the cabinet when opened.
Scribe the long-grain shoulder with the marking gauge to finish the hinge mortise layout.
Set the bit depth by laying a hinge leaf on the router’s baseplate. Route a test mortise on a piece of scrap and check for fit. The hinge leaf should be flush with the top of the mortise. A 1/4-in. straight-tip bit is a good choice for routing the mortise.
Rout the hinge mortise freehand, staying about 1/16 in. inside your layout lines. For a really clean cut, move the router in the opposite direction that you would normally rout: a technique called climb cutting. Routing in this manner prevents tearout, and it’s easy to control the router because the cut isn’t very deep and the bit diameter is relatively small. A scrap block clamped to the bench steadies the router’s baseplate.
Square the mortise with a razor-sharp chisel.
You’ll need to drill pilot holes for the hinge screws before securing the new hinges to the door and the case. To make the drilling job foolproof, use a self-centering bit.
Hanging the Doors
With the hinges attached to each door, press the loose leaves into their respective mortises in the case and install the screws. Now open and close the doors and inspect the fit. Your doors should swing as smooth as silk, with the doors flush to the face of the cabinet, and even gaps all around. If you notice some unevenness, a little judicious sanding with some 180-grit sandpaper wrapped around a block can usually fix the problem. Once you’re satisfied with the fit, mark the doors for knobs or pulls and install these along with your favorite catch hardware. Case closed.
Shave the shoulders by chopping lightly with a sharp chisel. It’s best to sneak up on your layout line, making several thin cuts until you reach the end-grain shoulder line. Clamp a block behind the long-grain shoulder to support this delicate area and take multiple cuts until you reach the shoulder line. Finish up by paring into the corners to clean up any left-over slivers of wood.
Drill for hinge screws using a self-centering drill bit. Lay each hinge in its mortise and drill through the hinge and into the door. Rub a little wax onto the screw threads to lubricate them before driving the screws home.
Brass screws break easily! Use the same size steel screws first and install the brass screws after fitting and finishing are complete.
Uh-ohl We accidentally trimmed too much off one edge of a door. Luckily, it was a long-grain edge and there’s a simple fix. Re-joint the edge, then glue on a thin strip to increase the door’s width. The strip should match the stile in grain and color and be slightly oversize in width and length. Trim it to fit after the glue dries. You’ll never see the fix!