Tall MCM Serpentine Lamps For Kathy
This story is all about making a custom pair of tall, Mid Century Modern Serpentine table lamps. The design is shown in this rendering and they'll be handmade in black walnut with a rubbed oil finish, 3-way switch and brass hardware.
ABOUT THIS DESIGN: These beautiful lamps are quite intricate to build and will require fairly high precision to accomplish a balanced visual appearance and structural integrity. Note that there are 4 sections to the lamp body set at 90 degree intervals which are each mirror images and an exposed, smooth brass tube runs vertically through the center of the lamps. This design poses 2 challenges right from the start; 1) how best to join all 4 serpentine sections at their center points, 2) how to build the serpentine shapes with sufficient integrity to withstand normal use and carry the tension loads between the top and bottom of the lamp which holds the lamp and base together. Let's start with joining the 4 sections.
This illustration shows an overhead view of the serpentine sections. They are 3/4" thick which is quite slender and where they meet (in the center of the lamp) there is little material surface area to form good glue joints.
The center of this joint will also have a 3/8" diameter hole drilled through (for the brass tubing to pass through) and this would further weaken the joint. Several joining options were reviewed and the one that offers the strongest joint is a short wooden tube that adjoins the serpentine sections; this is shown in the following illustration.
Note how the inside edge of the serpentine sections are curved to match the curvature of the wooden tube; this provides the greatest surface area for the strongest glue joint and even with the center hole, the walls of the tube are approximately 3/8" thick. This joint will require very precise shaping of the serpentine edges (where they meet the tube) but it will be a strong clean joint.
Next up is the integrity of the serpentine sections and distributing the tension loads. Note in this illustration how the serpentine sections are thinner towards the ends of each arc and wider in the center.
Note also how the wood grain runs vertically in the serpentine sections. The thinner serpentine sections might be susceptible to fail with the grain if the serpentine shapes were made from a single piece of wood. So, to reinforce these sections, the wood will be laminated to offset the grains (similar to a plywood lamination). This will make the serpentine sections quite strong laterally and vertically. Next, the top of the lamp receives a brass, cone shaped piece that rests on the top of the serpentine sections and when tension is applied to hold the lamp together, the tops of the serpentine sections which extend inside the cone, will be squeezed together so the 4 individual pieces tend to act as a single piece. This should allow for lighter tension loads needed to hold the lamp together and should help spread those loads more evenly through the lamp. Cosmetically, the bottom edge of the brass cone should transition as smoothly as possible to the serpentine sections and this will require quite accurate carving.
Enough on the technical challenges with the design; now let's look at making the lamp. First up is cutting and preparing the blanks for the base which will be turned on the lathe. First, resawing a black walnut timber 3" thick x 7 1/2" wide, to a thickness of 2 1/4". This photo shows how it's done on the band saw.
...and here's a photo after resaw which gives an idea of the original thickness and the separate boards after resawing.
... and here are the same boards with the resawn surface up to show the grains and colors.... all looks good.
next the thicker board needs to be cut into round blanks for turning on the lathe, here you can see one is done.
Because of the shape of the base there is no good way to hold the blanks in the lathe so each surface can be turned. So, a sacrificial surface from pine is made and glued to the top surface, then the faceplate (which screws onto the lathe) is attached to the pine surface. The bottom surface of the base will be shaped first, then the sides, then the a small portion of the top surface. Once done, the faceplate will be removed from the blank and the base can be attached to the lathe by a different type of faceplate (a 4 jaw chuck).
When the pine surface is attached to the blanks for the base, it should be as close to center as possible. Note the dowels in the center of the blanks, these are used to center the pine blanks.
Here you can see the pine blanks being glued to the walnut blanks.
clamping pressure is applied using the lathe tailstock while the glue dries.
Once dried, the faceplate is attached and here you can see one walnut base mounted into the lathe and ready to turn.
The serpentine sections are made up of 4 mirror images so a full size template is needed to get very consistent serpentine shapes. Here you can see the shape roughed out on a 1/4" x 1/4" grid on a piece of 1/4" plywood.
.... and here is the finished template, after cutout and smoothing all the edges and curves; it looks great.
Once the template is made, it's time to laminate the walnut sections and this takes quite a bit of preparation before gluing. First the larger boards get re-sawn on the band saw into the correct thickness. Here you can see the boards cut to 5/16" thickness and three boards will be laminated for each serpentine section.
The edges along the long side of the boards need to be very straight; these are the edges that will receive the shallow arc that adjoins the wooden tubes in the center of the lamp. First, one edge of each board is smoothed perfectly straight with a hand plane.
Next, the boards are trimmed to size in the table saw and this puts a very straight edge on the opposite side of each board.
Here you can see all the boards have been edged but the face surfaces are still rough from re-sawing so they need to be smoothed and this is done with a surface planer.
Here you can see the boards are planed to the finish thickness which is just over 1/4", both sides of each board are planed so they have smooth flat surfaces for gluing.
Once the boards are planed (surfaced), they are cut to size for gluing and here you can see them ready for glue-up. At this point the boards are also paired into sets of three with best possible grain and color matching and to ensure the grains running lengthwise in the boards are offset from each other for strength.
Here you can see one set of boards glued and clamped. The boards for each serpentine section will be laminated the same way.
It takes several days to get through gluing the serpentine sections because the boards need to stay in the clamps until the glue is dry which is usually about 24 hours and then another 24 hours after they come out of the clamps to relax before they are ready to cut into the serpentine sections.
Recall that the serpentine sections will be joined in the center of the lamp by sections of wooden tube. These are turned on the lathe with a 3/8 dia. hole running through the center. This center hole is what the brass tube in the center of the lamp will run through. Here you can see one of the wooden tubes cut on the lathe. Sizing and alignment of the center hole needs to be quite precise so the brass tube fits and looks right when the lamp is assembled. The outer diameter of these tube sections, which is 1", also needs to be quite precise for good alignment of the serpentine sections.
Here you can see different sections of the walnut tubes on the actual brass tubing that will run through the center of the lamp; the walnut tube sections are not sized to their final length yet, this will be done when the lamps get assembled. The outer diameter of each tube section looks very consistent at 1", alignment and sizing of the center hole looks very good with less than 1/64" play around the brass tubing.
And here you can see two of the laminated panels with the serpentine template positioned as the panels will be cut, the brass center-tube which will run through the center of the lamp and the wooden tubes positioned as they will be in the finished lamp. Next up will be turning the bases then beginning to cut and shape the serpentine sections from the walnut panels.
Turning the bases - here you can see the bottom or underside of one base has been turned. The recess in the bottom is for the concealed weight and the small hole in the center has been drilled through to the top and this is where the brass tube and wiring will run.
The bevel on the side of the base needs to be cut before the base is flipped around to cut the top. Here you can see the edge of the top diameter being set so the beveled sides can be cut to the correct angle.
Here you can see the beveled sides are cut and its time to cut the top surface so the base is removed from the lathe, the faceplate is removed from the base, the base is flipped over and reinstalled on the lathe using a different type of faceplate, a 4 jaw chuck.
Here you can see the base has been reinstalled on the lathe and it is being cut to the correct thickness. The sacrificial board which was glued to the top of the base blank (for mounting the first faceplate) is turned away and you can see the only remaining portion (the white wood in the center of the base) when this photo was taken.
Here you can see the base fully turned and ready for finish.
One last check to make sure the weights fit within the recesses in the underside of the bases, they fit well.
Here you can see a check for correct distance using the serpentine template - from the top outside diameter of the base to the bottom of the serpentine sections where they meet the base, these also look good.
The panels which the serpentine sections will be cut from have slight variations in thickness so they are run through the surface planer one last time to make them all the same thickness.
Next, the inside edges of the serpentine sections need to be perfectly flat and straight for correct alignment in the center of the lamp; here you can see this is done with a hand plane.
Next the serpentine template is used to layout identical shapes on the panels.
... and here you can see the inside edges of the panels have been routed into an arc to match the arc of the small wooden tube sections. These sections of wooden tube are the joining areas for the serpentine sections. Here you can see them test fit for placement against the serpentine layouts.
Next is cutting the serpentine sections from the walnut panels, here you can see this in process.
The walnut serpentine sections are all cut and rough sanded, here you can see them test fit together, they look great and the alignment of the center brass tube through the center wooden tubes is very good.
... the next 3 photos show additional test fits of the serpentine sections on one of the bases, note the base already has one coat of finish, the grains and finished color are beginning to stand out. The measurements, alignment and spacings all look really good.
additional spacing and alignment checks before assembly.
... and one last spacing and alignment check before assembly; these all look very good.
Time to begin assembling the serpentine sections. Here you can see the center wooden tubes being glued into position on the first serpentine section of each lamp. Each serpentine section gets additional sanding and very slight adjustments for best fit, then it is glued into place until all the serpentine sections have been joined to form the lamp bodies; each lamp will have 4 serpentine sections.