Introduction: Mahogany & LED Dinner Table Lamp
This is my dinner table lamp, and how i made it.
I always like to make my own things, so when i moved to a new appartment, I decided to make my dinner table lamp myself. I wanted something a little different, modern and good looking but not too flashy, so i decided on a mix of warm wood and LED lights.
I hope you enjoy this instructable, and find inspiration for new projects of your own.
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Step 1: General Plan and Drawings
I started up by drawing a few sketches, to get the design right. I also tried out different ways to hang it, to get it just the way i wanted. After I was done drawing by hand, I drew the lamp in SolidWorks, just to visualize it a little better.
I liked the idea of hanging it in steel wires, but i didn't want any extra wires for power, so i had to run electricity through the very wires it is hanging by. This begged the question if I should insulate them for safety (and yes i probably should have), but i felt that would ruin the aesthetics, so i had to make sure the power was as low and safe as possible in the wires. This meant i had to transform the power from the wall down and make sure there is a short circuit protection, before reaching the suspending wires. On the plus side, it also meant i had to stuff less electrical things into the lamp itself.
Because i wanted it to look as clean as possible, i had to hide every screw and electrical wire in the lamp. I wanted a piece of wood hanging by wires with warm white light coming out from underneath, nothing else. Magically stuffing wires inside a piece of solid wood seemed a little out of my reach, so the solution was to make it in sections, and vow to make the best glue joints I've ever made.
I decided to have 4 vertical strips, on top of one horizontal strip, making it a 40x50x500mm lamp.
Having the plans ready, i could start thinking materials
Step 2: Materials and Tools
I have to be honest, i had to adjust the drawings a little, after I went to the wood shop, because i couldn't get exactly the length i wanted. It wasn't much, and it had no real effect on the looks.
40x10x2500mm strip of mahogany
40x10x1000mm strip of birch wood for the wall mount
3 meters of 2mm steel wire, the "soft" kind (some types are more flexible than others)
Crimps for the wires
Four wire connectors
A power supply unit (PSU) going from 230V to 12V with short circuit protection (kinda important, due to the exposed steel wires)
A small strip of warm white LEDs, i had some leftovers from when i did my ceiling lights. I bought them on eBay
A length of tubing for insulation
A few screws, some wood glue and some finishing oil i already had lying around.
Total cost was about 80 dollars.
For tools, i only really used a disc sander to cut down on time, but that's not really necessary.
Step 3: Cutting the Vertical Wood Pieces
Start out by cutting the mahogany into 5 equal lengths. I originally wanted my lamp 50cm, but had to make it 48 to have a little leftover for cuts and some for the mount, but it didn't really matter in the design. Make the cuts nice and as precise as possible, but don't spend too much time getting the lengths completely equal at this point. It's much better to wait until it's glued up, that way you can have a slight tolerance when gluing it.
Next step, decide on which pieces have the prettiest surfaces. Only 3 pieces will be visible, and on each of those only one side will be facing outwards, so find the 3 best and be extra careful not to scratch or damage them.
The remaining two pieces will have holes cut in them, to house the transition from steel wire to electrical wire, and to secure the wire from being pulled out. You don't need to make these super accurate, you'll never see them again after it's all glued up.
Step 4: Cutting the Piece on the Bottom
The flat piece on the bottom wil have a long slot cut into it, where the LED strip will be placed in.
The LED strips can be cut to length in 5cm intervals, so i just held it up over the length of wood, and cut it as long as possible. This length, plus a little extra would be the length of the slot that had to be cut in the wood. I drew it up, and drilled down either end with a 11mm drill. The LED strip is 10mm, so I thought i'd leave a little room so spare. After i had the holes, I used a scroll saw to cut the middle piece. I cut it inside the line, and sanded it smooth afterwards.
Step 5: Gluing the First Pieces Together
The first pieces to glue is three vertical strips. One without any holes, with the prettiest surface outwards and the two with the holes for the wires. Smear a thin layer of wood glue on the sides, wiping off excess with a finger. Don't use too much, it'll just leave a mess that you'll have to clean later.
Make sure when you clamp it down to have the edges as flush as possible. The more flush they are at this point, the less you have to sand off later. Use lots of clamps to distribute the pressure evenly, but don't use a ridiculous amount of force. You risk squeezing all the glue out and making bad connections.It's a good idea to wrap it in cloth or a paper towel, to not damage the outside surface.
Step 6: Installing Wires
Before gluing on the last pieces, remember to put in the wires.
First though, a few holes need to be made. The holes for the steel wire was 2mm, and the holes for the electrical wire was 1,5mm. I marked the holes for the steel wire by first drawing a perpendicular line over the top, where I later would sand the rough ends to. From that line, i took a compass, set it to a certain length, long enough that the holes would go into the cavity i made in the two middle pieces. By using the same setting on both ends, i made sure that it would be very close to the same position in either end.
The holes for the electrical wires were made much the same way, except they had to have a certain distance between them. This was to not have any visible wire sticking out underneath. To get the length right, lay up the LED strip, and mark out the most discrete place for the wires. The LEDs should already be cut at this point, from when you made the slot in the bottom piece.
To install the wires, i started by placing the wire connector on the end, and then crimped it to a loop as tight as possible. In an appropriate length from the loop, i bent the wire 90°, so it would sit nicely without any bending moment. Put the electrical wire in the connector, predrill a small hole for at screw, and fix the loop in the wood. Make sure the screw is not long enough to go through the wall, otherwise it's back to square one.
Thread the electrical wire through, and put some tape around it so it doesn't accidentally slips back inside. It would be impossible to retrieve it once it's all closed up.
Probably a good idea at this point to connect the power, just to make sure it works. Oh and mind those exposed steel wires, they should not touch when there's power through them.
Step 7: Close Up the Blank
This step is not very complicated, just simply glue the final vertical piece on. Remember to make it nice and flush, and prioritize the bottom part. The top can be sanded down, but the bottom has to sit on top of another piece, so sanding it could cause small gaps where you remove material. So prioritize the bottom, so you don't have to remove so much there.
Step 8: Install the LED and Bottom
Next up is to install the LEDs, so warm up the soldering iron and solder the electrical wires to the LED strip. It's a good idea to keep track of polarity, so you don't connect them wrong in the PSU. Expose the tape, and stick it to the bottom. Make sure it's straight, and also dry fit it with the bottom piece of wood, to make sure it fits in the slot.
With the LEDs installed, you can glue the bottom part on. Be careful not to use too much glue, you don't want it flowing over the LEDs when you squeeze it on. The more time you spend aligning it now, the less time you'll spend sanding it down. Distribute the pressure as evenly as possible, the long thin pieces need a little extra attention.
Step 9: Sanding...
This step is time consuming to say the least. Mahogany is really hard, so sanding it takes a long time. It's tricky to sand around the steel wires, but take your time and make it as smooth as possible. You can actually end up making the seams nearly invisible, it's definitely worth it. I used 220 grit, and gave it a quick pass with 400 in the end.
Step 10: Making the Ceiling Mount
The ceiling mount was made with a strip of birch and the remainder of the mahogany. I simply made a little box, with a removable lid. The lid was mounted to the ceiling, and the box slid over it with the lamp hanging from the box. I pre drilled holes for the screws, to protect the wood from cracking. Make sure the holes are aligned to the lid, I did this by drilling them with the lid in place.
I also cut out a slot for a cable tray, where I'd run my wires to the wall. If you have wires in the ceiling, you can make a hole in the lid, and run it through there, I just had to bring the wire all the way to the wall.
The steel wires are kept in place with a set of wire connectors, which also serve to adjust the height so it's level. Immediately after the connector, i placed the insulation tubing, to avoid short circuits.
Step 11: Oiling It Up
With a mixture of linseed oil and turpentine, wipe all the surfaces over, to bring out the colour of the wood. Mind the LEDs, i don't think they're that happy about oil. Give it a few rounds of oil, mahogany is really slow to absorb it so it takes some time.
Step 12: Flip the Switch
And admire your new lamp :)
Just one thing - this is not a very kid-safe lamp. If you have kids, or pets who might accidentally short the wires, go for insulated steel wires. I don't think the 12 volts are enough to do any damage, but it's not worth it to test it out.