One of my favorite designs (and maybe the most versatile) is a flat-panel door with square edges on the frame pieces. This design is relatively easy to build and looks great in a variety of settings, from traditional to modern.
I've made a lot of these doors over the years, and in doing so I've developed methods for working faster, smarter and better. To follow these techniques, all you need are basic woodworking knowledge and access to a planer, a table saw, clamps and a drill press or drill guide.
Each door is made of five components: one panel, two vertical stiles and two horizontal rails. The panel is 1/4- in.-thick plywood centered in a frame of 3/4-in.-thick solid wood. The panel fits in a 1/2-in.-deep groove in the inside edge of each stile and rail, and the rail ends have tongues (tenons) that fit in the grooves in the stiles. When assembled, the panel edges and frame joinery are hidden.
My construction techniques require that the stile and rail stock be exactly the same thickness (3/4 in. or very close to it). The tenons and grooves are made with two saw cuts, one cut relative to each face. This process centers the tenons and grooves in each stile and rail, and it eliminates alignment issues that typically occur when making cuts relative to only one face. This is why it's critical that the stile and rail stock be the same thickness.
The overall size of each door is determined by a few factors. The first is the size of the cabinet opening. I always try to make doors close to twice as tall as they are wide; they look and function best when made in these proportions. That means using two doors over wide cabinet openings.
The next factors in determining the door size are how the door will fit on the cabinet and the type of hinge that the door will use. A door can cover the cabinet opening in an overlay, lipped or inset style. The easiest type to make, an overlay door, rests on top of the cabinet face frame (or the box in the case of a frameless cabinet). The amount of overlay is partially determined by the hinge you use, so you must buy the hinges before you start construction.
My favorite hinge for this type of door is the overlay concealed 35mm European-style hinge (see SOURCES in PDF below). This hinge mounts to the side of the cabinet or face frame and in a 35mm-dia. mortise in the inside face of the door. These hinges are big, and some people consider them unattractive, but they are hidden when the doors are closed and I like their ease of installation and functionality. (For more about hinges, see "Hinge Options," in PDF below).
The hinge determines the amount of overlay on the hinge side of the door. The remaining overlays should be a minimum of 5/16 in. and allow for at least 1/16 in. of space between doors.
I make all of the stiles and rails for a typical cabinet door 2-1/8 in. wide. I like that look, and that width allows for enough space to comfortably mount European-style hinges.
It is helpful to make a scale drawing of your cabinets that includes the proposed door size, overlays and gaps. Doing so will help you determine the door sizes and give you a feel for what the doors will look like. One final design consideration is the material and finish you will use. When your design work is done, make a list of all the doors and sizes you'll need.
The next step is to figure out the door-part sizes (see illustration in PDF, below). Remember to include the length of the rail tenons when you calculate the length of the rails. The tenons should be at least 1/2 in. long so there's plenty of gluing surface on the rail-to-stile joints. Longer tenons are necessary for larger doors, such as tall pantry-cabinet doors.
With your cutting list in hand, it's time to buy the wood and head to the shop. You can use 3/4-in. S2S (surfaced two sides) lumber from a home center, but you'll have much better luck if you buy thicker or rough-sawn lumber from a hardwood lumberyard and then plane it down to 3/4 in.
Rough cut the stile and rail pieces 1/4 in. wider and 1 in. longer than their finished dimensions. Plane the stock using a thickness planer (photo 1). Plane equal amounts off of each face, alternating faces as you go. Do not change any setting when making the final pass. Now cut the finished lengths of these pieces, but hold off on cutting the widths.
Plane all of the stile and rail stock to exactly 3/4 in. thick. Make extra stock for testing joint cutting and in case you mess up a piece or two later. The entire door-making process depends on the stock's being the same thickness.
Rough cut the panels 1/2 in. wider and 1/2 in. longer than their finished dimensions. Check the thickness of all of the panels to determine their consistency. Use the thickest piece as a sample for setting up to cut the rail tenons.
The rails are intentionally wide at this point because cutting the tenons causes tear-out on the edges, and cut- ting the finished widths later will remove the rough edges. This also means that the grooves are cut after the tenons, but you will need a groove to test the fit of the tenons. The solution to this dilemma is to make a test groove in scrap wood (photo 2); then you'll cut the tenons to fit the test groove. Afterward, you'll cut the actual grooves to fit the tenons.
In a piece of scrap wood, cut a test groove that matches the thickness of the panel stock. The panel should slide in the groove without force and without play. This groove will be used to fit the rail end tenons, which are cut next.
Before you crosscut the rail tenons (photo 3), test your setup on scrap wood. Cut the finished widths of the stiles and rails, and sand the sawn edges smooth. Be careful not to round the stile end inside edges where the rail ends fit. Finally, cut the grooves (photo 4). Make these grooves fit the rail tenons, and cut them slightly deeper than 1/2 in. so the joints will be tight when assembled.
Cut the rail end tenons with a dado blade and table saw. Cut one side, flip the rail over and cut the other side. Use a miter gauge and stop block to set the cuts so they are 1/2 in. long, and set the blade height so the tenon fits snugly in the test groove but is not difficult to insert.
Cut the grooves in the stiles and rails. Use a flat-top 1/8-in.-kerf ripping-style saw blade. Make two passes, flipping the piece around for the second cut. This centers the groove in the workpiece.
Cut the panels to their finished sizes, making sure they are square. Finish sand the panel faces. Assemble the doors (photo 5). Then clean up the glue, and sand the faces and edges smooth.
Glue and clamp the frame around the panel. Do not glue the edges of the panel; it should "float." Avoid applying glue near the inside joint corners to minimize squeezeout there, which would be difficult to clean up.
Hinges and finish
Hinge-installation instructions are included with most European-style hinges. Test your hinge-hole drilling setup on scrap wood; then drill the hinge-cup holes in the doors, and mount the hinges (photo 6). Hang the doors on the cabinets to check the fit. Trim the edges where necessary.
?Mount the hinges to the doors. Use a 35mm-dia. Forstner bit to bore 1/2-in.-deep hinge-cup holes. Make sure the hinge arms are square to the door edge.
Finally, remove the hinges so you can finish the doors. Ease the sharp edges of the doors with sandpaper; then apply the finish. After the finish has cured, complete the doors by installing your choice of handles and reinstalling the hinges.