Raised panel doors
Wood is a hydroscopic material that will expand and contract as the relative humidity changes. This movement must be taken into account when constructing furniture. Fail to account for this seasonal expansion and contraction and your panels will split and your joinery will fail. You may remember the article (‘Dealing with Wood Movement‘, Jun/Jul ’09, Issue #60), where the dangers of wood movement were discussed.
There are three elements in a frame and panel door: the center panel, the rails, and the stiles. An easy way to keep the rails and stiles straight is to remember that ‘stiles’ and ‘sides’ both start with ‘s’. Each of these components can be made on the router table with the correct selection of bits. In this article I will outline the three methods I use most often in my shop.
Panel raising options
You can choose from a back-cutting bit (1), a regular panel raising bit (2), or a vertical raising bit (3).
Rail and stile, matched set options
You can use a commercially made set of bits or you can make your own set that are just as functional.
Forget the numbers
Set the height of the bit using the thickness of the material to start.
Two cuts in one
The back-cutting bit removes one step from the machining of the panel.
Adjust the bit after the first cut so the lip is 0.125" thick.
The Rails and Stiles
Rail and stile bits are available in two forms, matched and reversible. When making a rail and stile door with a reversible bit, the end grain is cut first and then the cutters must be removed from the shaft and then reinstalled in a different orientation for the long grain cuts. With a matched bit set, each profile is a separate bit and both have been perfectly matched to each other at the factory. One of the major advantages of a matched bit set is that all of the pieces are routed face down on the router table, which helps improve alignment. Any 1½ HP router can be used to machine the rails and stiles.
To machine the rails and stiles you will need a router table with a solid fence. Ensure that you mill some test pieces to use when setting up the router bits. As with all router table operations, the end grain surfaces are routed first and any blow-out or chipping is then routed away when the long grain edges are machined. To avoid any confusion, I have used a felt tipped pen to mark a number 1 on all of the end grain rail and stile bits I have.
With the cutter mounted in the router table, raise the bit until the top edge of the end grain cutter is even with the top edge of the material. Set the face of the fence so that it is even with the surface of the ball bearing. You can place a ruler against the bearing and then move the fence forward until the ruler sits flush against both sides of the fence as well as the bearing.
To rout the end grain you will need some form of a cross slide that will run along the face of the fence and keep the material perpendicular to the fence. Some router table fence systems have an elaborate cross slide that runs very smoothly and flips out of the way when not needed. Before you throw your hands in the air in frustration at the prospect of needing to purchase yet another expensive piece of equipment to complete a project, rest assured that while these cross slides are nice, they do nothing that a simple piece of plywood can’t do just as well. To make your own cross slide, cut a 12″ x 12″ square of ¾” plywood and sand the bottom and the edges. Fasten a handle to the top and apply a coat of paste wax to the base to keep it sliding smoothly on the router table. Place the cross slide against the fence and then register the material against the front edge of the cross slide. Move the whole assembly past the bit to make the cut. The bit will cut into the leading edge of the cross slide, acting like a sacrificial back-up block, preventing the material from blowing out at the end of the cut. Measure the shoulder and the lip. The shoulder should be approximately ¼” with the lip being approximately ⅛”. When you have set the correct height, rout all of your end pieces. Be sure to rout a spare piece to use as a set-up guide for future sessions.
Rout the Stiles
Use the set-up guide to set the correct height for the long grain cuts. With the bit installed in the table, line the groove cutter up with the shoulder on the set-up piece. Make a test cut to confirm that the height of the bit is correct. If there is a slight difference between the faces of the two pieces, it can be easily sanded out. If you are not achieving consistent results, add a set of feather boards to the fence on your router to maintain a consistent downward pressure on the material.
The Center Panel
Unlike machining the rails and stiles which can be done with a 1½ HP router, raising panels on the router table will require a little more power. You’ll need to run a 2 HP or greater router if you plan on spinning these large bits. For the large horizontal bits you’ll also need a router with speed control because large diameter bits should not be run at full speed.
The center panel of the door can take a couple of different forms. If you are building a more traditional looking shaker style door, a simple flat plywood panel will be the most appropriate option. A solid wood raised panel might be more appropriate if you’re building a traditional kitchen cabinet door. A flat plywood door is the simplest, most stable option. Simply rip the material to length and width to fit the frame. A door with a solid wood raised panel involves a little more work on the router table before the panel is ready for the door.
When gluing up the boards for the raised panel, arrange them so the grain forms a pleasing pattern. When using solid wood, keep in mind that the curved edges of the panel will expose grain that will run in different directions than the face of the panel once it has been raised.
The procedure you use to rout the center panel will depend on the type of bit you are using. Whether the bit has a back-cutter or not and whether it is horizontal or vertical, will dictate different methods. I’ll describe the method I use in each case.
If you only have a single speed router, then you will need to use a vertical panel raising bit. With this type of bit, the panel is run vertically against the fence and you’ll need to use a second bit to cut the rabbet on the back edge of the panel.
The more common panel raising bits are the large horizontal type. To rout the center panel with a bit with a back-cutter, set up the panel raising bit in your router table so that the top of the tongue on the rail is lined up with the bottom of the back cutter. You’ll likely need to make a test cut or two because it’s impossible to set the height of the bit using the rail directly. Because of the back-cutter, the bit will be cutting on both sides of the panel at once and it has to be at the correct height right from the start. To make incremental passes with this kind of bit, you will need to increase its projection from the fence in successive cuts until you have reached the full depth.
When using just a basic panel raising bit without a back-cutter, you will need to change your approach. Because the bit doesn’t have a back-cutter, you will need a separate slot cutting or rabbeting bit to relieve the back edge. If you are using ¾” stock and you only raise the front of the panel, the surface of the panel will sit proud of the frame or the edges will not fit into the grooves. Before setting up the panel raising bit, use a slot cutter or a rabbeting bit to rabbet the back edge of the panel. Set the depth of the rabbet equal to the distance from the edge of the groove to the back of the rail/stile. With the rabbet routed in the rear face of the panel, set up the panel raising bit and raise the front of the panel. Because this bit doesn’t have a back cutter, this cut can be made in increments by raising the bit after each cut. Make one or two rough passes to hog off the bulk of the material and then make a final light pass for the best quality cut so that you have a tongue on the edge that fits snugly into the grooves in the frame.
No matter which method you use to raise the panel, make an extra piece to use as a set-up guide for future operations.
Variations On a Theme
Most of the frame and panel doors I make are more like a shaker door and feature a flat panel with rails and stiles without an edge treatment on the inner edge. As most of the matched rail and stile sets involve some sort of an edge treatment, I ended up making up my own matched set from slot cutter components. Simply mount a ¼” slot cutter on one shaft and a ¼” and 5/16″ cutter on another shaft. Use some washers and shims between the ¼” (top) and 5/16″ cutter (bottom) to ensure they are exactly ¼” apart. This set is the equivalent of a matched rail and stile set and can be used the same way. Set the top of the cutter equal to the top of the material and then rout all the pieces face down on the table.
Many of the doors I use in my work feature a flat panel in a plain frame, so I have developed my own method of making this type of door that is even simpler that using a raised panel set. As with the other methods, prepare all of your rail and stile material ahead of time and then set up a ¼” spiral bit or a slot cutting bit on the router table. With the rail and stile pieces cut to size, I use a dowelling jig to place two dowels in each of the four corners and then I move to the router table to cut the grooves. If you use a slot cutter, run the material horizontally on the table, face down. The slot will need to run into the first of the dowel holes but this poses no problem. On the rails, the groove will run the full length of the edge, but on the stiles it will need to be stopped or it will show on the top and bottom of the finished door. If you are using a ¼” spiral bit the procedure is similar but the material is run on the vertical against the fence. Since vertical spiral bits are more fragile than the slot cutters, use a slower feed rate or make multiple passes to reach the full depth.
Assemble the Door
Before moving to the assembly stage, the center panel must be finished first. A panel that is finished after the door is assembled may leave an unfinished edge exposed when the panel shrinks. As well, finishing the panel separately before assembling the door means there are no corners to create areas where finish can pool.
The pieces, especially the routed profile, must be sanded before applying any finish. Without the right tools for the job you can spend considerable time trying to sand the profiles and by sanding them by hand you run the risk of distorting the profiles. If this happens it will be most apparent in the corners where the rails and stiles meet. One tool on the market to sand routed profiles is the Sanding Mop (stockroomsupply.com), and a bench top drill press. Mount the sanding mop in the drill press and run each of the rails past the spinning mop, first in one direction and then in the other for a perfectly sanded edge that maintains its crisp details.
To assemble the doors, lay out some clamps and get your material and adhesive organized. The center panel should float in the frame to allow for the seasonal movement that will occur. If the panel is glued into the frame, the reason for building the frame will be defeated as the panel will not be able to move freely and it will most likely crack the joints in the frame as it expands or crack the panel as it contracts.
The panel should fit snugly to keep it from rattling as the door is opened and closed. If the panel fits somewhat loosely, it can be held tight using one of several commercial products. Panel barrels or Space Balls from spaceballs.com or Black Bridge Online (blackbridgeonline.com</a>; 1-800-826-8912), are small rubber cylinders and balls that are inserted in the slots before the panel is installed and they keep it from rattling while allowing it to expand and contract. You can make your own ‘rattle snakes’ to serve the same purpose in the shop using waxed paper and a tube of silicone caulking. Simply draw out a ¼” bead of silicone on the waxed paper and when it has cured cut the snake into short sections and insert it into the grooves.
If you wish to glue the panel in, place a small amount of glue in the center of the two rails and then center the panel in the frame when assembling it. This will lock the panel in place while still allowing it to expand into the frame at the sides.
To assemble the door, use a brush to apply a thin layer of glue to the rails and then clamp everything up. Check the diagonals to be sure the door is square and examine each of the four corners to be sure that the end of the stile is even with the edge of the rail. There is nothing to lock this joint in place, so it may shift slightly as the clamps are tightened. Assembling the door style that I use is the easiest of the bunch. Simply use a brush to apply glue to the dowel holes, insert the dowels, the panel, and clamp it up. In this case the corners are locked in place and there is no need to check either the diagonals for square or the corners for alignment.
Used everywhere, for the sides, the doors and even the back of a cabinet, the frame and panel is one of the most common elements in woodworking. Using these techniques will provide you with many options for their construction, depending on the equipment you have in your shop.