Curved cabinet doors
What's the most efficient way to build radius frame-and-panel doors in-house? May 15, 2002
I need to construct several doors for a curved front cabinet (28" rad). I like the look of traditional rail and stile. My thought is to use a bending form and laminated strips of 1/8" luan ply and 1/8" red oak for final layer. I would love to simply run these through a cope and stick cutter, but I don't believe the groover would work on the curved rails. I could possibly remove the groover and run the profile and cope cuts and then run a 1/4" router bit to cut the grooves separately. My other option would be to dowel the rails and stiles and apply sticking (profile) afterwards. Originally I planned on flat 1/4" ply panels for door insets but am now thinking raised panel. For these I'm considering 3/4 stock ripped to 1 1/2" slats, bevel edges, glue up, and sand to perfect curve. Then run the panel over a shaper cutter to create the raised profile. This project is for myself - I'm not trying to make money on it - but would like to hear what you think of my plan.
Buy the doors.
I have a similar project on the drawing board. I intend to build my own doors. Perhaps gluing up three 1/4" thick solid strips would be a better approach. The panel could be laminated as well. The side to be raised needs to be thick enough to handle the depth of the panel raising profile. Maybe two layers of 3/8" thickness would make the bend. The stiles will have a share of the radius as well. A full-scale layout is needed here to determine how thick of stock is needed for them as well as making the glue up forms. I believe the forms need a little more curve to them to account for spring back. As far as machining goes, I think a hold-down centered on the cutter would allow running the cope and groove together. I have not tried any of this yet, so proceed with caution.
Artisans create art. Business people buy profit. In your shop or from an outsource, obtain the best component for the most competitive cost. In this case I'd buy the doors and make a few more boxes 'cause I could at a profit.
Unless this is a matter of pride or personal challenge, buy them. You most likely can't make them for less than someone who does this every day.
I think you should attempt the doors, since they are for yourself. You will probably be successful in not only building the doors, but seeing firsthand the cost and time of producing these in-house. The experience of what it takes to create something so complicated, while not profitable, still has great value and can do nothing but enhance a woodworker's skills. The next time this situation arises, you can make a buy-or-build judgement based on actual experience (my guess is you will buy them out).
If your pattern cutter cuts from the bottom and not over the top, you will be okay. Put a slight angle to your stiles when cutting the pattern, so that the stiles do not meet the curved rails at an angle that is made for flat doors. You will want to raise the outside of the rails 2-5 degrees. You will have to see which angle works for the radius that you are using. When laminating your rails, make the radius tighter than needed. When you take the laminated pieces out of the form, they will spring back. Make a mock-up door and see how it works and see how your jigs need to be. Once you have the jigs made, you can make curved doors, for that radius, all day long.
From contributor P:
I've made lots of curved doors, raised panel with French curved tops, bow front doors with compound curves and even raised panel bombay. If you're only doing a pair or two, and have a shaper, you can do it yourself and have full control over the results. A tilting arbor shaper is nice, but not a must. First, to simplify things, be sure your cabinet is a true radius - that way you can effectively use your sticking cutters, less groover, to cut your profile.
I start with the rails first, but I use a solid block and layout the section with Mylar glued to the edge. I angle the ends and then make a jig to run the cope normal to the arbor. If you have a tilt, this is where you benefit. Next, make a curved base to attach to your table and run the stick without the groover. Do this with a router. If you are doing elliptical or compound, you will have to custom grind tooling 90 degrees for your profile.
For your stiles, make them thicker and hand plane/sand to agree with the rail. The raised panel can be done many ways. For larger panels, your method works great. Just make a contoured jig to aid in holding the panels while working and sanding. For first timers, expect to spend about 20 hours per door.
I have a very upscale clientele, so making curved raised panel doors is something I do all the time. A few tips:
If the radius were tighter, laminating would be the way to go, but with a radius that large, there won’t be too much cross grain at the tenons, so there is no reason the rails can’t be milled out of 10/4 stock. If you have a CAD program, make a full size drawing of the rails, glue them to the blanks, then using a steady hand, band saw the blanks.
Once you have the blank components milled, the first thing you need to do is to run the pattern and groover on the stiles.
Next you’ll need to determine the proper angle for running the cope on the rails. Make the blanks for the rails extra long so you can do a little trial and error. After each test cut, insert the rail into the stile and compare it to a full size drawing. Once you’ve found the proper angle, cope all the rails.
You are absolutely right about not being able to use the grooving cutter when doing the rails. These must be done on a table router using a 1/4” bit and a custom fence. Be sure to plow the groove using multiple passes or you’ll get chatter for sure. Before you do that, though, run the pattern cutter by itself on the rails. It’s a touchy feely kind of deal because you have to keep the rail perfectly centered on the cutter as well as perfectly perpendicular to the shaper table at all times. Making multiple passes is expected and you’ll be able to tell by sound if you’re cutting wood or not. Don’t linger though, or you’ll burn the wood.
Shaping the panel raise on the curved portions of the raised panel is accomplished using a similar technique. Obviously, you’ll be putting the cutter in upside down and running the shaper in reverse. Shaping the straight part of the raised panel is tougher. Here’s the trick. Be sure to have fence perfectly parallel with the table slot when you adjust the depth of the fence. Assuming your slot is 2/4” wide, rip a piece of 3/4” scrap material to the correct width so that when you stand it up in the groove, and lay the raised panel on top of it, the cutter will leave a 1/4” tongue. If the tongue is too thick, the “stand” needs to be higher. If it’s too thin, be glad that you made the raised panel blanks a bit oversized so you have a second chance.
Don’t be frustrated if the doors don’t come out as perfectly as you’d hoped. The more you do, the better you’ll get. There’s no better exercise for improving your skills as a craftsman.
In this instance, making them and getting to know what it takes would be a good thing. It's one more notch in the proverbial belt. Later when time is more important, he can decide for himself whether to outsource or not.
From the original questioner:
You did point out some details that will save me on trial and error. I know that outsourcing the doors would be a heck of a lot easier and probably cheaper. We want to make our own doors because we already do a fair amount of arch work - this is just a natural progression. Also, this project requires the making of several 3" wide aprons. Being that I have to do the form work and laminations for these, I might as well make a couple more and make the doors. In addition, this project is filling a void in a specialty high-end market. I definitely see money for the future. I might as well work out the bugs now and then change into my salesman suit. Right now I'm trying to see if there is a more economical way to create the doors in-house. For example, as suggested, using 10/4 stock. I've thought of this but I believe it will be more costly than laminations. Will have to work it out to see.
From contributor P:
One note on laminations, as they seem like a very cost-effective way to go. They can cause difficulties in machining. The bent rail basically is built up of thin layers that are in both tension and compression. The glue line is pure shear. When the sticking and grooving is cut, the wood can behave in a nasty manner. If your profiles are small, it's not much of a problem. Big profiles can result in twisting after machining. Give yourself extra material and take your time. Curved doors can be quite a bit of work, but I find them quite enjoyable.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
When I make curved RP doors, I steam bend them. I find this a much easier way to go than laminating and milling. You simply make your stick cut when the rails are flat and then steam bend them. Your only jig work would be cutting the ends and making your cope. If you're real good at steam bending and calculation, you can make your cope cuts before bending.
I do the same thing with raised panels - cut first and then bend. Bending against the grain is a little tricky and requires jig work, something you can't get away from even if you laminate.
Comment from contributor B:
Here is a good link to an article on how to make radius frame and panel doors:
Radius Cabinet Job - Project Review