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Arched Top Louver Doors ?


I have been asked to build arched top louver doors ( about a 16' radius) for the first time after building many louver doors. I'm not sure they are possible since the top rail dictates that the blades taper to zero as they ascend. Does anybody have a clean detail/solution ? Or is my brain shrinking as I get older?

9/4/15       #2: Arched Top Louver Doors ? ...
Leland Thomasset  Member


Like the one below but bigger

View higher quality, full size image (1944 X 2592)

9/4/15       #3: Arched Top Louver Doors ? ...

Thank you Leland; The applied moulding in your photo is a great way to let louvers taper off behind it but doesn't seem like they would shed water very well ? My application is exterior.

9/4/15       #4: Arched Top Louver Doors ? ...
Leland Thomasset  Member


This was for a courtyard there were 4 of them. We did them about 8 years ago. They were fun and interesting to build. It took my CNC plus a 5 axis CNC to get the louvers cut into the arches. They have not had issues that I know about. Although I do agree that the moldings would not shed water. I do have drawings for them and 3-d models if interested let me know

9/5/15       #5: Arched Top Louver Doors ? ...
David R Sochar Member

I learned this method 45 years ago in a curved stair shop that did a lot of curved work of all kinds. A bit labor intensive and uses up some material, but it works well and makes for good and accurate mortises. We used it mostly for full round and half round louvers, and the 4th step would be a bit different for them, but the principle works for any curve.

This solution requires a plowed curved rail, with the plow sized to receive the assembled slat mortises. The straight stiles can be conventionally mortised, or also use plowed mortise inserts, though that is more trouble than needed.

In this example, the rail is 1-3/4" thick, and the slat mortise insert is 1-3/8" thick. The slats are 2" wide and have a 1/4" lap, or blind.

S4S stock to 1-3/8" x 1-3/4" by longer than your arc. 1. Plow the first half of the mortise, centering the plow in the thickness. Flip the part and repeat. This is done with a tablesaw and 1/4" dado. Make as many parts as you think you need, then a few more. Be sure that your plows enter and exit the parts in the center so they will easily align for the next step.

2. Glue up for the width (height) of the arc you will need, making careful alignment so the mortises match up. This quick example shows the arc to be 90 degrees. Have a part that is longer than your plowed parts and 1/16" thinner and narrower than your plows, wax it up heavily on all sides, and run it into and thru all the mortises to clean out the glue squeezeout. Wipe off the glue and repeat if necessary. Do this several times to make for clean mortises.

3. When the glue has cured, clean up the assembly faces and layout the inside and outside cut lines. I like 3/8" deep mortises since they can add some structure to the finished louver panel. Determine where your arc needs to start/stop so as to align with the straight stiles of the panel. Cut the inner arc on the bandsaw, and clean up the cut surface.

4. Put the slats that will end up in the mortises into the curved slat mortise insert so they pass the 3/8" deep second, or outer radial cut line. Leave them long on the other end. Saw the second line, freeing up the part, now 3/8" x 1-3/8", and cutting the slats with the proper complex curve on their ends. (My favorite part).

Glue the insert into the plowed rail and then cut the opposite ends of the slats for assembly.

View higher quality, full size image (2475 X 1913)

9/5/15       #6: Arched Top Louver Doors ? ...

Thank you so much for the thoughtfulness and time you have invested in answering my question. Such an elegant solution so typical for the history of our craft. I have been building sash & door for 35 years and have never seen this method. You need to seriously consider teaching an advanced joinery class in your shop someday similar to what Joe Calhoon is doing with his euro sash & door. It would be great to tour your shop and learn from a master carpenter like yourself. I really mean it! Take care and thanks again.

9/6/15       #7: Arched Top Louver Doors ? ...

David you never cease to impress me with the knowledge you have accumulated in your career.

That is an elegant solution to a challenging problem .

9/11/15       #8: Arched Top Louver Doors ? ...
Mitch Suber  Member


Thanks so much David for sharing that procedure. I have no doubt this will improve our quality and save me countless hours.

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