Shoji lantern - take 2

These lanterns are a scaled down version of the one I made a while back but with some minor changes. These are about 5" x 5" x 12" overall. This time the wood used was Alaskan yellow cedar, compliments of a woodworking friend who gets the trimmings from a hot tub shop near his home. 

I went through the bundle and picked out the sections with the straightest grain first. The kumiko (lattice pieces) are fairly small - 1.5 bu x 2.5 bu (about .180" x .300"), but like any kumiko, they will be strongest if the grain runs the length of the part. 

The "posts" are 5.5 bu square and 8 sun long. I cut these long so that the required mortise work would not split an end. I trimmed them to final length just prior to final assembly. The post tops are planed to a low pyramid shape using this simple jig:

Again I used the haunched or shouldered tenon to allow part of the tenons to bypass within the post, as seen below. The layout of the parts was easily fouled up so I marked all parts and double checked the layouts of all cuts and grooves prior to making any shavings. 

Reduction is the name of the game with kumiko and the challenge is how to get the most kumiko with the least waste (and least wasted time). Best process that I could work out for these small kumiko was to plane your board within a few thousandths of final thickness, plane one edge square, then use a kebiki (marking gauge) that is set to just wider than the kumiko width and scribe front and back. Then take a sharp utility knife (box cutter) and scribe the kebiki lines deeper from both sides until you can split it off. The thin blade of the utility knife is pretty good for this. Thicker blades will crush more wood and you will have to plane that off. Re-plane the edge of the board, then repeat until you have all the kumiko you need (or run out of board). 

Now you have kumiko with 3 almost finished sides and one split side. Check the grain run on each kumiko as you lay them side by side with the split edge up, and gang plane them until the split roughness is just removed. Now check thickness all around and take very light cuts to bring them all down to the final dimension or a couple thousandths thicker (so you can finish plane the parts before assembly). You may also notice that the splitting imparts a curve to the kumiko and that that curve tends to go away once the split edge is planed down to undisturbed wood again. You want the kumiko straight and free of any compressed wood from splitting that may cause distortion later as is expands. This project is so small that is not likely, but on a door or large panel it matters a lot.

At this point my project work was put aside so I could modify a neglected plane dai to make a kumiko thicknessing plane. This entailed mounting two rails and a spring loaded pressure bar to the bottom of the kanna dai. I started by cutting a dado across the dai about 1 cm in front of the mouth, boring some sockets for 3 coil springs I found, and drilling and tapping 4 holes to hold the two thickness-determining rails to the dai. A picture is worth a thousand words. 

With the dado done I made the pressure bar out of a scrap of cherry and made similar sockets for the same springs. The bar has to have a low angle chamfer so the kumiko stock does not snag on the leading edge of the bar when planed. Also, the bar has to recess below the kanna bottom so as not to bottom out during cutting. Some mods like this include a pressure bar "behind" the blade as well, so you may want to consider it.  

The rails have notches to allow the bar to protrude beyond the bottom of the plane. The pan head screws that hold the rails to the dai required counter-bored holes so the screw heads would not protrude. A Forstner bit took care of that (used it before drilling the through holes). Only the rails are to contact the bench top while planing. 

Once the plane was done I could plane a bunch of parts to thickness at once. You can make other rail sets of differing thicknesses to suit your needs. The stiles and rails of the panels were 2.5bu by 2 bu and were half lapped at the corners and eventually glued. Now back to the project.

The top panel sits in a notch in each post, so just it's corners are supported. Not the strongest, but there was not a lot of material left in the top frame pieces due to handle post tenons and the 2.5 bu deep grooves for the shoji panels. 

The bottom panel is just a thin square panel with corners notched out to accommodate the posts. All of the lower frame pieces are grooved to fit the panel, so it is securely locked in but floating (though not enough to rattle). 

So here are all of the parts prior to final fitting. The handle was cut out roughly with a saw and then trimmed to final shape with a sharp kiridashi (single bevel knife). The knife has to be long and thin to make the small radius inside curves on the bottom of the handle(s). A kuri-kogatana would be good, but I used a knife I had made previously from a HSS jointer blade. The trailing edge of the flat side of the blade was rounded on a grinder to allow a smaller cutting radius.  

And the pair after initial assembly.

For the shoji paper I used an old paper with a chrysanthemum design. I measured and cut the paper carefully to avoid waste. 

Gluing to the shoji panels (using Nori brand craft glue) was easy with a small paint brush to lay down the glue. Careful alignment of the paper before pressing it onto the glue is important to avoid the need to trim (which is not so easy on small panels like this). Once the glue has dried thoroughly I spritz the paper lightly with water from an atomizer. This tightens up the paper and can remove minor puckers.  

That completes the panels so we are left with installing the actual light sources. Again I chose battery powered LED lights. The criteria were the same: Warm white LED (color temp 3000). AA or AAA batteries to reduce weight. Hi and low power settings. Long battery life on low setting. Easily adapted to a wooden lantern. And the winner is: the Mini-Hozuki from  

The Mini-Hozuki is not cheap but it does fit the criteria above - except the easy mounting bit. I was hoping to take them apart but they are made in a way that any form of modification will likely damage the electronics. So a cradle needs to be made to hold it. That is a blog post in itself.

Battery bracket + guts
Bubble is the switch. Push hard.
The lamp is controlled by pressing down on the bubble lens. This lens is a slight diffuser, but the original Hozuki design relies more on the silicone skirt to diffuse some of the light. The bubble is attached to a silicone diaphragm that deflects when you press on the bubble. This means there is no easy to access power switch - you press the bubble. Hard. About 5 lbs. of pressure. And I found that the actual switch is at one point on the perimeter of the dome. You need to find that one point and make your switch mechanism put the pressure there in order to minimize overall pressure required to activate the switch. 

The key things are the warmer color temp (not cold blue), long battery life, light weight (3 AAA batteries plus minimal electronics), and about the size of a billiard ball. And it dims and has pseudo-candle flicker mode. Too bad the mounting and switch mechanics are not ideal. 

Peel off the label to remove hook.
The magnetic hook (later removed).
And then when all is assembled you get the following results:


Siavosh said…
This is great, thanks for sharing! And great to see you blogging again, looking forward to hopefully more.