How would you size this angle slat to the back top piece

[Brian Runau]

Thinking about building a couple mission chairs. In this detail the bottom of the top piece in the back is curved, which I think is a nice detail. How would you get the vertical slat to match the angle in the bottom of the top piece? Thanks. Brian

mission chair detail.jpg

[Zachary Hoyt]

I would assume that there is a full size mortise in the top of the back, and the slat is just stuck into it. Then you wouldn't have to match the angle, and it would be much stronger than the other way.

[Jim Becker]

That's often done with a combination of removing most of the stock for the tenon with machinery and then refining the tenon and shoulder using hand tools to match the curve. You can scribe the curve on the material if you dry assemble the top piece, sides and whatever component(s) that those attach to where the slats go at the bottom. It's a bit of fiddling but that's what woodworking is about. For the mortises, do them before cutting the curve in the top piece if at all possible. It's easier to cut them when the piece is rectangular...

[Tom Bender]

Make a pattern from cardboard and manilla folder paper. If the slat is 12" long make a manilla stub for each end about 3" long. Make a cardboard slat 11" long and tape the ends to it in place. Voila! a template in ten minutes.

[James Jayko]

You could also cut a full length dado on the top piece, and fill in the in between gaps after the fact, then rout them flush. I did that on a morris chair; especially given that location, you'd never see it anyway. Definitely a workaround, but it'll probably save you A LOT of time...

[Tom Bender]

James offers a good approach. Otherwise you will be leaving small bits between mortices which will probably get damaged anyway. Install the fill-in bits as you assemble so the tenon shoulders cover the joints. Hold them in place with glued on crosspieces.