Crown Molding for Radiused-Corner Cabinet Tops

An explanation of how to mill curved crown molding for application to radiused corners. June 23, 2006

I am building a cab with 2 1/4" radius on the front corners of the sides. How do I run the crown moulding around each corner and maintain the same radius as the corners?

Forum Responses
(Cabinet and Millwork Installation Forum)
From contributor D:
Turn it on a lathe. Cut into quarters.

From contributor B:
You need thicker stock for the corners; thick enough to give proper projection (moulding) when cut to match radius of cabinets. Then match the profile of straight pieces.

From contributor H:
What contributor D said! We have been doing it that way for many years.

From contributor P:
Machining the segments on the lathe is really the only good option. The only trick is duplicating the profile, as the only time you can check it for accuracy to the original is after you have cut it into segments. I usually make a bondo impression of the original profile, then slice it into a 1/8 wide gage. From here I can quickly turn the profile on a face plate and gage it without removing. You also want to quarter the segments very carefully so as not to lose too much material due to the saw kerf. I usually do this on a bandsaw and clean up on a disk sander.

From contributor J:
Am I missing something? After you cut the piece into quarters, how is it applied to give the look of wrapping the radiused outside corner? You still have a 90 degree back corner on the pieces.

From contributor D:
If the inside radius of the crown (outside radius of the corner) is 2-1/4" and the crown's projection is 3", then the outside radius of the crown is 5-1/4" or 10-1/2" in diameter. The turning you make will be 10-1/2 diameter x the height of the crown. Each of the four segments is 90 degrees and - I assume - each of your cabinet faces is 90 degrees from the other. The axis/centerline of the lathe/turning is the vertical face of your cabinet. The straights will butt up to the turned curves. Or am I missing something?

From contributor E:
If you are mounting the crown on the top of the cabinets, then you don't need a radiused back. If you are mounting the crown on the face of the cabinet, then you have to turn a center hole on the lathe that matches the radius of the face of the cabinets, in this case a 4 1/2" diameter hole (2 1/4" radius). Or this could be cut on the bandsaw after removing from the lathe.

From contributor M:
Lathe turned crown moulding works great for small radius work, but when you go to a 12" deep quartered cabinet, you need another method. Since we run our own crown, we take the head, with knives, mount it on our heavy duty tilting arbor shaper, tilt the arbor to the proper degree. We built jigs to hold the segmented raw wood block. The jigs are designed to allow the work to be slowly moved into the cutterhead and the powerfeed keeps the wood rotating. It is an absolutely beautiful thing to behold. After shaping to size, we then cut the block in quarters and join to the straight runs. We also create arched crown using similar methods.