Tenoning Shutter Slats

Advice on joinery for old-style storm shutters. December 19, 2009

I would like to reproduce a set of original New Orleans style, movable exterior shutters. I can do everything but cut the round (1/4" D x 1/2") tendon or post from a solid slat. Can anyone suggest a method to do this? I thought of setting up a jig with a plug cutter. Is there another way?

Forum Responses
(Architectural Woodworking Forum)
From contributor G:
The fencing industry would have the correct tool to do this. It should be something like a pencil sharpener for your drill.

From contributor S:
The machines that produce integral round tenons were almost all custom-made in the last 50 years. I used to work with one that was dated in the 1920's, and updated with pneumatics. It would hold the slat stock, pull it up to a stop - then a swinging arbor with two dadoes on either side of a larger diameter cut-off saw would swing in while the slat holding fixture and slat would rotate about 500 degrees. While it rotated the arm would feed in slowly and cut the tenons on the previous slat and the next slat. As the arm moved in, the larger diameter cut-off saw would then cut the slats apart, leaving an integral tenon on each slat. I could easily yield about 1,000 slats per hour. The slat stock had to be very accurately dimensioned or slats would not feed correctly.

One tip is to make the tenons so they bottom in the stile bore, and give some clearance between the slat and stile, or else the slats will not work when painted. Too much gap, and light comes in, and so do complaints. Also, crown the stiles to tension the slats, and then the slats will stay where you set them in the complete shutter. I spent three years making 16 to 20 movable slat shutter panels every day, nearly all with customized equipment.

From contributor S:
Lee Valley Tools has a bunch of power tenon cutters you put in a drill, but I am not sure if it works on a slat. I believe they are meant for doing willow furniture.

From contributor S:
I got so carried away with my description of a custom machine that I neglected to mention other methods (much slower). Today's crafty solution is to buy a ga-zillion little plastic pegs/tenons and put them in the ends of pre-drilled, profiled slats. Accuracy drilling into end grain is the chief problem here, as well as added time and more parts to deal with.

Another way is to start out with your slat stock as wide boards, S4S'd, then cut it to length, including the tenons, and then tenon the ends, then rip the slats apart, and then profile. Square tenons will be the result, and contrary to popular belief, will fit in round holes. The drawback is that profile has to happen after length.

From contributor T:
Dado cutter in table saw. Jig/cradle to locate and rotate over cutter. Not too bad an investment for short runs - it goes fast after set-up. Jigged plug/tenon cutter will work but you would have to pre-cut the shoulders on the saw anyway. Have fun making the shutters.