Tsuitate - Part 1

Tsuitate are free-standing screens designed to provide privacy for inhabitants of a house or shop that has doors open to a not-so-private area. Similar situation exists in my house so I figured a tsuitate would work nicely. Overall dimensions were roughly taken (approx 60" wide and 66" high, but final dimensions are not yet known). 

Conventional tsuitate vary widely in size and form. Some include shoji panels, but many do not. There are also multiple joined panel screens called byobu (屏風) used to block wind or draughts. Anyway, here is the scale drawing I will use. I sketched the shoji section a couple ways to see what they looked like. Final shoji will use spacing pattern on the left side and will be a single fixed screen with kumiko on both sides. Apologies for the distorted picture:

For materials, the top grille and center shoji are to be Port Orford Cedar (POC), the decking-grade variety. The framing needs to be solid so I am using approx. 3 inch square African Mahogany. I had trouble finding 12/4 material and the mahogany was one of a few lousy choices. If it ends up not looking right I will find something else. Feet need to be substantial, typically heavier than frame stock. 4" x 4" might work. Will mock something up for scale before pinning dimensions down.

Work plan is to build the grille (done), then the shoji (half done), then the frame and feet. Joinery options abound on this one, as do the requisite basic mortises - 150 for just the grille and shoji. Get used to it.

The top grille is the focus of Part 1. This is designed to provide some privacy from prying eyes and does when viewed obliquely. The depth of the kumiko and the spacing thereof need to be mocked up and tested to get the desired effect. In this case they are about 3 bu thick and 1 sun deep (shaku scale).

Each kumiko has a 6 bu wide tenon on each end. The kumiko need to be precise in thickness because I was making tenons with 2 shoulders, not 4. Any variation would be obvious and possibly make for loose kumiko. Also, the shoulder to shoulder dimension needs to be consistent or when you assemble the frame you will have more gaps. It also has to match the frame ends (stiles) precisely so the corner joints close up properly. Take your time, use sharp tools. Make some extras, do practice cuts and joints on scrap.

For the corners Jay van Arsdale (my instructor) suggested a mitered open double mortise and tenon. Not sure of the technical name for this one, but here it is:

And here are the frame pieces prior to assembly. Assembly was difficult because all the tenons and mortises needed to line up. I worked slowly from one end to the other, then added the ends pieces of the frame last.

The outside of the grille frame will sit in a 2 bu deep groove all around so the outside of the frame is not particularly important. The rest of it is, so take care not to damage it in handling.