Basics of Frame-and-Panel Construction

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Wood is a wonderful material, but it moves with the seasons, expanding and contracting as the air gets more and less moist. The frame and panel is a tried-and-true way to contain that movement. If we made doors out of solid panels of wood, for example, they would show huge gaps in the winter and have no chance of closing in the summer, not to mention warping over time. But take that same panel and enclose it in a narrow frame, and you have a beautiful door that will stay flat and stable for generations.
 

The traditional frame-and-panel door has a solid-wood panel in the middle, enclosed in a groove around the inside of the frame. It is very important not to put any glue in that groove; the panel must be able to expand and contract freely. There's also some extra room in the groove to allow for expansion and contraction of the solid-wood panel. During seasonal changes, that panel will actually get a bit wider as it absorbs moisture.
 

Most door frames are only 3/4 in. thick or so, and so the groove can only be 1/4 in. or 5/16 in. wide. But a 1/4-in.-thick panel would feel and sound thin, so woodworkers traditionally have shaved down the edges of a thick panel to fit in a narrow groove. This is called a raised panel, because the bevels around the edges create a raised center section that looks quite nice.
 

Another option is to put a plywood panel in the middle. In that case, since plywood doesn’t move with moisture changes, you can glue the panel into its groove. By the way, the vertical frame pieces are called stiles, and the horizontals are called the rails. Just think of a fence rail to help you remember. Add glue to the joints and the grooves, insert your plywood panel, clamp it all together, and you have perfect doors. The doors seen at right will be painted, so the panel is made from medium-density fiberboard (MDF), and not plywood. 
 

The traditional way to build the frames is by forming full mortises and tenons on the ends of the pieces, and if you are going to have a solid-wood panel floating in the groove, this is probably the way to do it.

In the example at left, the edges of the panel have been beveled in order to fit into the groove. For your first doors, you might want to start out using a simple flat panel as opposed to these fancy raised ones.

 

 

Cope-and-Stick Bits are Fast and Easy

The easiest way to build frame-and-panel doors is with a set of rail-and-stile router bits, also called “cope-and-stick” bits (at right), based on some other old-time woodworking slang (there’s tons of it). These cut a groove and a molding on the side edges of all the frame pieces, and also cut a mating profile on the ends of the rails. The frame joints have only little stubby tenons, so they aren’t as strong as traditional doors. So you should use a plywood panel in these doors, and glue it into the groove. Then the doors will be extremely strong.
 

Step 1-At left, you can see the joint made by cope-and-stick router bits. Using the bits in a router table,  you first cut the groove and the molding on the side of all the frame pieces.

Step 2-Next, the other bit cuts a matching profile on the ends of the rails. A square push block keeps the piece square as you push it past the bit. Don't try this maneuver without adequate support behind the workpiece.

There are lots of ways to dress up a frame-and-panel door, other than the raised panel in the middle. You can have all kinds of moldings around the inside of the frame, and the joints can be mitered at 45° for a more contemporary look. Also, the panel is a great place to show off especially beautiful wood grain.