This is my first instructable, a plan for a simple plywood and 2 x 4 desk that I designed and made several years ago.
The idea was to use a single sheet of hardwood plywood, and some basic hardware to build this desk for between $75 and $100. It could probably be built for less if you changed some of the materials.
Unfortunately I didn't document the build process at all, so I only have pictures from several years after it was built, and some pictures of a much larger version that I built later. I've included pictures of the other desk (a similar design), and the completed desk as it is today.
Step 1: Planning
Planning for this desk is pretty simple. Since the goal is to build it from a single 4' x 8' sheet of plywood, the length is dictated by the available length of the plywood, and the height of the desk.
I laid my desk out on a sheet of graph paper using a 4 squares per inch rule.
Step 2: Planning: Legs
The first step is to decide how high you want the desktop. Standard desktop height seems to be around 28", but I decided to build mine at the same height as a keyboard drawer for ergonomic reasons (~25").
So the height of the legs is measured off of the side of the plywood, and then split in half to form two legs.
Step 3: Planning: Top
The next design consideration is how deep you want the desk to be (I chose 30" for mine).
The wood left over from this cut is used to provide a backing panel for the desk to strengthen the design.
Finally, how long should it be.
The simple answer is "whatever is left once the leg portion is removed", but you can always shorten it to fit your needs or space. At most this will be around 72"
Once you have the basic measurements, you can calculate how much support wood you'll need as well.
Step 4: Materials
Since it's a "Single Sheet of Plywood" desk, you'll need a single sheet of hardwood plywood (sometimes called "Cabinet Grade").
I used 3/4" white hardwood (possibly Maple or Poplar) from "the Big Orange Box", but there are other species available. ($30 - $50 depending upon where you get it, and the species).
You'll need some material for providing support to the desk, and attaching the legs and back to the top.
In my case I used 2 8 foot 2x4s and about 3 foot of 2x2, but you can substitute other dimensions of lumber, or even use hardware for joining the corners.
You will want at least one board for the center support since the plywood will warp at that length without some support (I added mine after building when I realized that it was needed). ($5 - $10)
You'll also need some "wood veneer edge banding" to hide the edge of the plywood once complete. (I think I paid about $30 for a roll, again at the Big Orange Box place).
Screws / glue / finish. I used wood screws, but didn't glue this one. I'd glue it if I did it again. I used a "one step" stain and finish. ($10 -$40 depending upon finish choice).
Step 5: Cutting
I had the "Big Orange Box" store do all of the cuts on the plywood for me.
They will do one or two for free, and then there is a fee per cut after that ($1?). Unless you change the length of the desk, it should only be 4 cuts so it won't add much to the price, and their panel saw does a great job on these long straight cuts.
Step 6: Assembly: Back
I'm using some pictures here from another version of this desk, so the sizes and lumber are a bit different. The concepts are still the same.
Since this is the back of the desk, and mine will always be against a wall, I just screwed straight through the back plate, and into the corner support. You could screw through from the other side, but you'll have to be careful not to punch through the plywood.
I first attached the backing plate to the corner supports, then attached a full length 2x4 turned on edge to support the desktop.
Step 7: Assembly: Legs
Next the legs were attached:
I started by attaching the top supports to the back. These supports will attach the legs to the top.
Next the legs were attached to the side supports with wood screws. I screwed through the outside, very close to the top. These screws can only be seen if you are on the floor looking up, but they could have been filled with wood filler or even run through from the inside.
Step 8: Assembly: Top
The top is laid on, and screws are run from the supports up into the top. You have to be very careful here not to run the screws too far into the top, or you'll have a screw sticking out!
Once I had assembled my desk, I realized that the top needed additional support, and added the 2x4 shown in the pictures. If it's planned ahead, it could be done a bit better, but this is functional, and can't be seen unless you crawl under the desk.
Step 9: Finishing
The next step is edge banding. This covers the raw edge of the plywood with a wood veneer, and makes it appear to be a solid slab of wood. Most big box lumber places will have this banding near the plywood (make sure it's the same type of wood, or looks like your plywood).
It applies with an iron (the iron heats the glue on the back and attaches it to the wood), and then can be trimmed, sanded, and stained to match the rest of the desk.
The last step is to sand and finish the desk, just like any other wood project.
Step 10: Enjoy!
Overall I've been very happy with this design. I used if for a couple of years before giving it to my son, and building a larger version with a hutch.
I hope it helps someone design and build an economical desk.