Making Cathedral Doors
A COMPLETE RECIPE FOR MAKING BEAUTIFUL CATHEDRAL RAISED-PANEL DOORS
Cathedral raised-panel doors are beautiful, but they can be intimidating to make. After many years of teaching students how to make these doors, I’ve got a trick or two up my sleeve to simplify the process and remove some of the fear factor. Here’s a tried-and-true recipe to help you safely and successfully make beautiful doors.
There are a few specialized tools you must have to make cathedral doors. Start with a suitable router table. It should be equipped with a 2-hp or higher variable-speed router that accepts 1/2-in.-shank router bits. You’ll also need a bandsaw or jigsaw for cutting the curves and a set of door-making router bits. The bits and a template set will set you back several hundred dollars, but they are a big part of what makes this technique airtight. The good news is the router bits are not specific to cathedral-top doors; they can be used to make any frame-and-panel door.
You’ll need a two-piece matched rail-and-stile set to make the frame. It’s easier to get good results with a two-piece set than with a one-piece reversible bit. With a two-piece set, you feed all the pieces face down. Reversible bits use one arbor with removable cutters. Some parts are machined face up, others face down. This often results in poor alignment between rails and stiles. Plus, it’s a hassle to have to change cutters on the arbor. Bits with a 1/2-in. shank will produce less chatter and a smoother cut than those with 1/4-in. shank.
The end-grain cutter is used only on the rail ends and produces the tongue and the mating profile to the molded edge. The depth of cut is controlled by a bearing that rides against the tongue. Mark a number 1 on the end of the shaft with a permanent marker, because it’s the first cutter you’ll use.
The long-grain cutter is used on the inside edge of all the frame pieces. It makes the groove for both the panel and the tongue on the end of the rails. It also forms the molded edge you see around the inside of the frame. Label this bit with the number 2.
Use a back-cutting panel raiser to make the panel. The main cutter cuts a broad profile in the face of the panel. At the same time, the back cutter sweeps material off the back of the panel to leave a perfectly sized tongue for the groove in the frame. Our favorite bits come with two bearings: The large-diameter bearing is used for the first pass and the small bearing for the final pass.
Make the Frame
First, cut all the frame pieces. For a good-looking, stable door, make the frame from straight-grained wood.
Next, on your router table, set up the end-grain cutter for machining the rail ends. Cutting end grain before long grain helps prevent blow-out on the rails. Here’s a memory device for you: Machine the Rails before the Stiles, because R comes before S in the alphabet.
Mark the back of all the frame pieces. They get machined with their good faces down, so you should be looking at the mark on the back for all the cuts.
Note: Run the end-grain and long-grain cutters at full speed on your router. 76 I How to Make Kitchen Cabinets
Recommended Tool: Coping Sled
Get a coping sled for making the end-grain cuts on the rails. The sled uses a quick-release clamp to hold the rails with a firm grip. A replaceable backer block keeps the rail square to the fence and backs up the edge of the rail to prevent blow-out.
Set the height of the end-grain cutter against a test piece in the coping sled. The cut should leave a shoulder on top of the piece that’s twice as thick as the lip on the bottom. You can tweak the height after a test cut.
Set the fence even with the face of the ball bearing. A straightedge makes quick work of this job.
Make a test cut, but don’t cut all the way through the test piece. You don’t want to cut into the backer block until the bit height is perfect. That way, the block can be used to quickly set the bit height the next time you make doors.
Check the cut. The height of the router bit controls the depth of the shoulder and the thickness of the lip. The tongue size is fixed. The shoulder should be about twice as thick as the lip. In 3/4-in.-thick stock, this works out to a shoulder depth of approximately 3/16 in. Raise or lower the bit as needed and make test cuts until it’s right.
Rout the rail ends. Remember, the back of the board is face up for all cuts. To ensure a uniform cut, keep consistent downward pressure on the sled at all times.
Rough-cut the arch in the top rail. Center the rail template on the top rail with the bottom of the pattern even with the rail’s bottom edge. Use a template that is the same length or slightly longer than the rail. Trace the template and use a bandsaw or jigsaw to cut the curve. Stay at least 1/16 in. but no more than 1/8 in. outside the line.
Flush-trim the rail with a template guide and a flush-trim bit. Use double-faced tape to adhere the pattern to the rail. The fence is replaced with a bit cover and starter pin assembly.
Set the height of the long-grain cutter by aligning the groove cutter with the tongue on the end of a machined rail. The top of the cutter should be even with the top of the tongue.
Make a long-grain test cut in a scrap piece. Use featherboards to hold the rail down onto the table and a push stick to drive the piece past the cutter.
Check your work by fitting a rail into the test piece. The faces of both parts should be flush. If they’re off by just a little —the thickness of this page, for instance—you’re probably OK. A tiny discrepancy like that will easily sand out after assembly. If they’re off more than that, raise or lower the bit to correct it. Make test cuts until you’ve got a good match.
Recommended Tool: Template Set
A cathedral template set is a matched set of rail-and-panel templates. A template can be fastened directly to the material to act as a guide for the flush-trim bit. A set typically covers a range of panel widths, generally from 9-1/2 in. to 22 in. Each pattern has a centering hash mark for locating the pattern on the wood. Sure, with careful layout and bandsaw and drum-sander work, you can make your own patterns, but it’s hard to beat the simplicity of commercially made patterns.
Don’t forget to mark the backs of all your parts, and pay attention to the marks. It’s very easy to flip a rail and end up with a piece that’s no good.
Caution! Make sure your bit guard is in place and the mounting bolts on the fence are just loose enough to let the fence slide easily.
Make a zero-clearance fence by slowly sliding the infeed half of the fence into the spinning bit. This eliminates most of the chipping that can happen on these cuts. You only need the zero-clearance fence on the infeed side.
Machine the long-grain edges of every frame piece, including the straight portions of the arched rail. Make sure the piece is face down. You should be able to see the mark on the back of the piece when you’re machining it.
Begin the arched cut at the precut section of the top rail. First position the rail against the starter pin without contacting the bit. Then pivot the rail into the bit so the bit enters the previous long-grain cut. Caution: Do not allow the bit to contact the end grain, as this typically causes it to grab the rail and ruin the piece.
Complete the long-grain cut by pivoting off the starter pin and riding the router-bit bearing through the entire length of the arched rail. Use push blocks to keep consistent downward pressure on the rail throughout the cut.
Make the Panel
Gluing up narrow pieces of wood is the best way to make wide panels. You’re more likely to get a panel that won’t warp, and it’s your chance to exercise some creativity. Look for interesting grain patterns or cool-looking pieces of wood with lots of character.
Large-diameter panel-raising bits must be run slowly, at no more than 12,000 rpm. Routers with 3-hp motors can easily raise the panel in two passes using the fence to limit the depth of cut. A router whose motor has less than 3 hp may struggle a bit. Use push pads to grip the panel and guide it past the hit.
Form the arch on the panel the same way you did the rail, but using the matching panel template. Use a square to make sure the pattern is set square on the panel. Center and trace the pattern, cut outside the line, tape the pattern to the panel and flush-trim the shape.
Set the panel-raising bit’s height by aligning it with a rail’s tongue. “Eyeball” the bit height so the bottom of the back cutter is even with the top of the tongue. Use the bit’s small bearing and set the fence 1/4-in, in front of the ball bearing. At this stage, the fence is back in.place of the bit cover.
Make a test cut on the long-grain edge of a piece of scrap. It’s easier to cut long grain than end grain, so make your test cuts on a long-grain edge. Make the first pass with the fence about 1/4 in. ahead of the bearing. Set the fence even with the bearing for the second pass.
Check your work by slipping the test piece into the groove and laying a straightedge across the face. The panel and the frame face should be flush. In this case, the gap means the bit is set too high. Adjust and test the bit height until it’s right. When the correct bit height is established, replace the small bearing with the large one.
Make the first pass on the panel with the face of the fence set even with the large bearing. The first cut is made on the panel’s bottom edge. Rotate the panel counterclockwise and make the second cut on the long-grain edge. Keep the panel moving in one continuous motion to prevent burning. Cuts 3 and 4 will require different setups.
Set up to cut the panel arch by removing the fence and clamping the bit cover and starting pin in place. Turn on the router and position the arch against the starting pin without contacting the bit. Rip the panel to width, but don’t cut it to length until after you’ve flush-trimmed the arch on top, just in case you have a problem with the flush-trimming step. Mark the back of the panel to remind you to keep it face down on the router table.
Start the cut by easing the panel into the bit so the bit enters at the previously cut corner. At this point, the arch is in contact with both the starting pin and the bearing on the router bit.
Rout the arch by pivoting off the starting pin so the panel is only contacting the router-bit bearing. Finish the arch, reposition the fence so it’s even with the bearing and make Cut 4 on the remaining long-grain edge. Replace the large bearing with the small one and repeat the process (Photos 19 through 22) for the final pass.
• If you’re making a door with rails and stiles less than 2 in. wide, its easier and safer to work with pieces wide enough to make two back-to-back pieces. After all the machining is done, rip the stock down the middle to create a pair of stiles or rails.
• Practice making a door with an easy-to-machine material, such as poplar or pine. Keep a successfully made door, dry-assembled only, so you can use the parts for future setups.
• Make extra pieces, just in case. Rails are especially easy to goof up. You’ll appreciate having a spare ready to go if you need it.
• Use straight-grained material for the frame and more open-grained pieces for the panel.
• Prefinish the panel before you assemble the door.
Recommended Gear: Bit Cover
A shop-made bit cover with a starter pin is essential, because the arched shapes can’t be cut with a fence. The starter pin acts as a fulcrum for easing the arched rail and panel into the router bit. The cover protects your hands and provides dust collection. The large plywood base allows you to clamp the cover to your router table.
Assemble the Door Sand all the pieces before putting the door together. Be careful when sanding the long-grain profile on the stiles. If you sand too much, the stiles won’t mate with the rails the way they should.
Prefinish the panel to guarantee the entire panel is coated with finish. That way you won’t have unfinished edges peeking out of the frame when the panel shrinks in winter. Prefinishing also prevents glue squeeze-out from gluing the panel to the frame, which would prevent the panel from floating in the frame. A glued-in, solid-wood panel is bound to crack as it tries to expand and contract with seasonal changes.
Have everything you need ready before applying the first drop of glue. Glue dries fast, and you don’t want the glue to start setting up while you’re running around the shop looking for a clamp.
Speaking of clamps, use good ones. Sure, you can make almost any clamp work, but parallel jaw clamps are the best by far. They stay dead flat, even under clamp pressure. If you only spring for one pair—and glue a kitchen full of doors one door at a time—you won’t regret it.
Glue in sequence from 1 to 5. Start with a stile and the top rail. Add the panel, then the bottom rail, and capture it all with the last stile. Keep the edge of the rail dead even with the end of the stile.
When you apply glue to the rail ends, make sure the entire profile is covered except for the areas just above and below the groove. This helps prevent getting glue on the panel.
Clamp the door gently. It doesn’t take much pressure to pull the rails and stiles together. Excessive clamping can bow the door. Measure the diagonals to make sure the door is square. If it’s not, loosen the clamps and rack them in the same direction as the longer of the two diagonals. Tighten the clamps, and recheck the diagonal.
Solid-wood panels expand and contract seasonally. When they’re at their smallest, they can rattle within the frame. You can take the rattle out with these silicone strips. Make them by squeezing 1/8-in.-dia. beads of silicone caulk onto a piece of wax paper. After the caulk dries, peel off the strips and cut them into 1-in. lengths. Set these into the grooves before you assemble the door. They’ll provide a cushion that allows the panel to expand but not rattle.
Sizing a Door
Before you can calculate the lengths of the rails and stiles, you have to know how the door Qwill fit over or into the cabinet opening. If the door will lay over the opening, its called an H overlay door. You must know the amount of overlay to make your rail and stile calculations. The size of the overlay —how much bigger the door is than the opening—can be affected by the hardware you use. So, get the hardware before you build your door.
If the door will be set inside the opening, it’s called an inset door. To calculate your stile and rail size on an inset door, you need to know the gap size between the door and the cabinet (usually about 1/32 in.). Many cabinetmakers cut the parts to fit the opening exactly and then trim the assembled door to create the gap.
Calculate the stile length by measuring the height of the opening and either adding the overlay amount or subtracting the inset gap’s width.
Calculate the rail length by first measuring the width of the opening. Add the overlay or subtract the inset gap amount; this gives you the door’s overall width. Now, subtract the width of the two stiles and then add the length of the two tongues on the ends of the rail.
Determine the width of the arched rail. First, measure the depth of the arch in the rail using the appropriate template guide. Make the top rail wide enough so that after the arch is cut out, the thinnest part of the rail top equals the width of the bottom rail.
Determine the panel size by dry-assembling the frame and measuring from groove bottom to groove bottom. Make the panel 1/8-in. smaller in both length and width to allow for expansion. On many cutters, the shoulder on the frame’s face is aligned with the bottom of the groove. This allows you to simply measure from shoulder to shoulder on the dry-fit frame.
Measure the tongue length on the rails. You need this number to calculate the rail length. When you figure out the dimension for your router bits (it can vary from manufacturer to manufacturer), keep it—you’ll use it for every set of doors you make with that cutter.
To determine the panel size, you first need to know the distances from groove bottom to groove bottom in the assembled frame. Most cutters align the shoulder on the frame’s face with the groove bottom. This allows you to take the necessary measurements right on top of the assembled frame.
Note: Size the plywood base so it can be clamped on your table at two or more points.