Electric Sofa Table
We have found that the electric outlets in our living room were not really serving our needs. They're fine for things that don't move, but not so useful for when you want to plug and unplug something. Outlets are mostly tucked away behind tables or chairs. It's not very convenient, for instance, when plugging in a vacuum cleaner or a laptop.
In particular, these days we often sit on the sofa with a laptop or some other device, and when they need to be plugged in, it is awkward to try and access power.
I considered attaching a power bar to the bottom of the sofa, either along the side near the front, or on the front near one of the corners. This would allow you to reach down and plug in your phone or laptop. However, it is also a tripping hazard. I just know that the cords will end up left there when the device is taken away. it's also rather unsightly.
Instead, my idea is to make a slender table and tuck it behind the sofa. Our living room is not large, so it needs to be skinny! This would give us a small shelf that could be useful. However, the main idea is that this would give me a place to add some electric outlets, on the two ends of the sofa table. So we would now have some power that is handy to the sofa, while still being discretely out of view.
Video Build
As an option, you can watch a video of this project, otherwise, read on!
Design
My table design is just 6" wide, and about 31-32" tall, so it would be just a bit lower than the top of the back of the sofa. I originally designed it in sketchup to be 68" long, but I ended up trimming that back to be 66". It's most of the length of our sofa, but still recessed on either side.
It has an ash top, and the bottom structure is baltic birch plywood, which I planned to paint black. The bottom structure of the table will be almost entirely hidden behind the sofa, which is why I thought painted plywood would do. The only part really meant to be visible is the top, which will be hardwood.
I made this Sketchup 3D design to help me plan out the project, but I did not fully follow the design. First of all, I changed the length. Second of all, I made the rails under the top to be full length, and not broken in two as in the sketch. I love using 3D software to help visualize a plan, but I still usually fiddle with things in the shop during the build!
Prepare Stock
I didn't happen to have a wide enough board available, so I glued up two pieces of ash to make up the top.
I also ripped some half inch Baltic Birch plywood (what I happened to have on hand) into three 5-inch wide pieces to use as legs. The sofa table will be long enough that I think that three sets of legs are justified.
I chose to use solid plywood for the legs (ie: the two ends), in part so that "stuff" will not roll behind the sofa and under the table. However, most floors are not perfectly flat, so it is a good idea to split each of the ends into two feet at their bottom. I taped the three legs together, and drew on some 8" tall angled feet. I first drilled hole at the top of where the angled cuts would meet, and then cut out all the feet at the same time using the bandsaw. (A jigsaw or handsaw would work here!)
Attach the Understructure to the Top
Normally when making a table, I make the understructure as one unit, and leave the table top separate. It is easier to finish the parts separately and then attach the top afterwards. In this case I was using wood that was not all premium -- I'm getting to the end of my stash of ash lumber -- and so the top had a slight twist to it and one of the rails had a rather pronounced bow in it. Therefore I decided to assemble the rails and then glue them carefully to the top.
The idea is that this will turn the top into a sort of "I-beam", and would hopefully eliminate the bends. Which it did, by the way. I used dowels to attach the ends of the understructure to the rails before gluing.
I also used the technique of tapping in some small nails, leaving them sticking out of the surface, and then clipping off the heads with some nippers. This leaves a small, sharp, 1/8" tall piece of metal sticking out of the wood, and it will act to prevent the rails from slipping when they are glued and clamped into place. I added two of these at each end and two in the middle of the underside of the top. (This is illustrated in the animated GIF.)
I then applied glue to the rails, positioned them, and clamped it to my work table, which has a flat top. I left it overnight and was very satisfied with the results.
Working on Legs
I then moved on to working on the legs. I traced out some electrical boxes and used a jigsaw to cut holes near the top ends of the two end legs.
The middle leg needed a notch cut into the top of it, so that an electric cord could be fed from one end of the table to the other, tucked up underneath the top.
I took the time now to paint the legs black. I masked off the top of each leg, so that bare wood was left available, as I then needed to glue the legs to the rails underneath the top.
I also wanted to add a crosspiece towards the bottom of the legs. This was a bit tricky, as the middle leg was in the way. So I cut the crosspiece in two. But now I had to deal with two crosspieces that met at the very thin middle leg.
I first installed one crosspiece, clamped it in position, and then drilled holes through the middle leg and glued in two dowels. Unfortunately I somehow do not have any photos of this process. The second crosspiece was then fitted into place with pocket hole screws into the middle leg. I used pan-head screws to fasten the crosspieces to the outer legs. I do usually try to avoid visible fasteners, but this seemed like the simplest approach for this project. Since the table is mostly hidden behind the sofa, I decided that there was no reason to get very complicated with the joinery here.
Apply Finish
I used a small roundover bit in my palm router to add a chamfer to the top, and then sanded it.
I am a big fan of Minwax Oil-Modified Polyurethane. It has the simplicity of a waterbased finish, and it still gives a bit of the warm amber colour that an oil finish adds. I brushed on three coats of finish, sanding lightly between coats.
Adding Electrical
The next step was adding electrical boxes to the shelf.
I added a regular duplex outlet at one end, and at the other end I added a special duplex outlet which also contained two USB charging ports. An electric cord with a plug on the end is connected into the first outlet, wired to the receptical, and then another wire continues on to the second electrical box at the other end of the table.
The wire is secured to the underside of the top with restraining clips -- these are the same that are used to secure electrical wire inside the walls in construction. I did remove the nails that the clips came with, as they are too long, and substituted short #6 screws.
I did not take photos of the process of wiring up the outlets. When DIY people show wiring online, and especially on youtube, it tends to attract a LOT of negative comments, which I just did not want to deal with. Also, I am located in Canada and electric regulations and power systems are different in various countries around the world.
As well, I think that the idea is more important than the details. If you are willing to tackle building a table, then I'm sure can figure out how to safely manage the wiring. This is basically just a customized extension cord. You could just build a table, and then attach a powerbar to one of the legs, and it would accomplish much the same thing.
Photo Gallery
Here are some photos of the finished table.
It's tall and skinny and long, and rather difficult to take photos of, but we are very happy with it.
It's been in use for a couple months now and it is very handy having those two outlets so much closer at hand.