Introduction: Twisted Bent Lamination Lamp
This twisted bent lamination lamp was my entry for the Rockler Bent Wood Challenge, hosted by the Modern Maker Podcast. The idea I had for the lamp was to create legs that had a helical shape. This was really hard to model in Google Sketchup, which is normally where I start designing, so I started by sketching a bunch of options, before finally settling on this design.
The lamp's twisted and bent legs connect to each other through solid wood stretchers, and in the voids are basic shoji panels.
Step 1: Making the Bent Lamination Strips
Bent lamination requires thin strips of wood that are pliable. I started by jointing and planing material to thickness, but you can also purchase pre-milled wood from the big box store.
To cut the strips, I used the table saw. In order to make strips of consistent thickness, I needed a rigid stop that wouldn't move, so I used the back of my featherboard. But you can also make your own thin-strip jig like this one from 3x3 Custom. In any case, it's important the stop doesn't move so you can get really consistent thin pieces, at about 1/32" or thinner.
Step 2: Making the Helical Form
To bend the legs into a helical shape, we need to create a helical form. For this, I used a 2-foot length of PVC pipe. I found 1.5" diameter pipe was best for this application, but you can bend around any diameter of PVC.
I started by marking a line down the length of the pipe. Then, I marked the end of the pipe at the two ends of the line. I got out a large sheet of paper and placed the pipe, line side down, on the paper, before marking on the paper where the line touched it.
I rotated the tube 180° from where I marked it, then marked just the back side where the PVC was touching the paper. Now I had three points I could connect into a triangle with a marker, before cutting the triangle out with a knife.
Then, I taped the triangle to the PVC, remembering to put the long leg of the triangle against the marker line I drew before. This gave me a helical shape that I could use as a guide to place masking tape across the hypotenuse, which was the guide I'd use when gluing the strips into a leg.
Step 3: Building Up the Legs
Now that the form is built, the building the legs is relatively easy.
Using spring clamps to hold a first strip around the form, I applied glue to one side of the remaining strips and stacked them with the glue side down on top of the first, one at a time, until I had a ¾” thick leg.
To make sure the legs laminated well, I applied pressure with a bunch of rubber bands and some strategically placed trigger clamps while the legs cured.
And after letting the legs sit overnight, I used the end of the form as a saw guide to cut the ends flat.
Once I had four legs, I started sanding. Let me tell you, this is a job for hand sanding. As much as I wanted power sanders, or rotary tools, or something else to make this process go faster, there was really no better tool for the job than a rounded block of wood and some sandpaper rolled around it.
Step 4: Mortising the Legs – Part 1
With the legs done, I had to create the joinery for the legs to connect to the stretchers. I have this surface that isn’t flat, isn’t straight, and is coplanar only in specific places, and I needed to get my mortises right so I would have a square lamp. I really had no idea where to start, but with some help from a friend, I created this contraption of a jig that holds my workpiece completely level and still. It's basically a jerry-rigged stack of blocks screwed or glued to each other to hold the legs still.
Now to actually cut the mortises, I had a couple choices: I could do it by hand and drill the waste with a drill press, but I wouldn’t be able to mark a square tenon on this piece. I could do it with a hollow-chisel mortiser — which is probably the easiest way — but I couldn’t fit the jig into the bed of the mortiser I have access to. Or I could use a router for the mortise and make round tenons. That’s what I decided to do.
Step 5: Mortising the Legs – Part 2
With the first mortises made, I had to figure out how to cut the second side. I was presented with the same problems as with the first side, but now I had the added complexity of making sure my mortises were square to the first. So I made another jig, which holds the leg square to the router on these two dowels you can see in the first photo. This held the legs still while I could route another mortise perfectly square to the first mortise. It worked like a charm.
Step 6: Creating the Stretchers
My stretchers started as 1/2" x 1/2" x 8" sticks of cherry that I ripped to size on the table saw. But because I had round mortises in the legs, I needed to make round tenons on the stretchers. So I decided to use the lathe to make round ends.
Then I dry-fit the stretchers into the legs so I could start scribing where they’d meet. As you can see in the second photo, the straight tenon shoulders meet a curved leg, so each leg needs to be custom fit.
To scribe the legs, I used a cheap compass, and once I had a line established around all four sides of the stretcher on each side, I used a combination of my Japanese pull saw, chisels, and a file, to massage the fit until each mated to the leg seamlessly.
The last stretcher doubles as a lamp socket. I used the drill press to cut out the recess for the lamp socket and some hand tools to establish a rabbet for the lamp socket to fit into two other stretchers.
Step 7: Gluing Up the Lamp
Once all of the stretchers were fit, I could glue up the lamp assembly. I found a lot of use in this homemade square, which is just a square corner of plywood with the corner knocked off and a couple of holes for clamps. This helped act like a third hand to hold pieces together. Otherwise, this was a relatively nondescript glue-up.
Step 8: Making the Kumiko Panels
The final part of the lamp assembly were the kumiko panels. I make the panels like I make any kumiko pattern, creating cross-laps for the frame on the table saw, then gluing the panel together. You can see more detail about how I do this in my Instructable here.
I backed all of the panels with some handmade mulberry paper using acid-free double-sided tape, before separating the individual panels.
Step 9: Sanding & Finishing
The final step was finish sanding. I used a hand sanding sponge and sanded up to 220, before finishing with a few coats of shellac. Between each coat, I sanded to 400 grit and remove the sanding dust with a tack rag.
Step 10: Assembly
With all components done, I could assemble the lamp by installing the lamp cord and lightbulb, then the four shoji panels.