Having a suitable workspace is crucial, but even the simplest desks can cost a significant amount of money. This instructable will show you how to build a folding or "murphy" desk out of an old table. It works great for a bedroom where it might be inconvenient to have a large desk all the time. I used a metal door we took out of my house but you could alternatively make this out of wood as long as you replace the tools listed with the appropriate tools and you may need to purchase replacements for certain

Supplies

Angle Grinders (saw for wood)

screwdrivers/impact driver

drill

tape measure

paint

scrap metal or wood and hinges (a door in my case)

Step 1: Gather & Measure

Gather your supplies and figure out the maximum length and height for your desk (width will be the width of the door). I found a nice spot between two closets with about a 3feet and a half between. I decided to make my desk three feet long and three feet high. Go ahead and disassemble the door.

Step 2: Chop-Chop

Now its time to cut the parts needed. Once the door is disassembled, Cut the door into the desired length (three feet in my case).

If you have one long hinge like the one my door came with, cut it into three feet as well and keep the rest for later. Otherwise, you will use normal hinges.

Now cut out the part of the frame where the hinges go to match the length of the desk.

Comment: if you have a long hinge when cutting the frame, try to make the pre-drilled holes line up with the frame and the door with the frame backward/upside down. This way you don't have to drill holes again later on. The door should open backward

Step 3: Wall Frame

Now its time to attach the legs to the frame. The open part of the frame will face up. The open parts of the legs will also face out, with the flat part facing what will be the wall. The back of the frame and back of the legs should be as flat as possible. If you're comfortable welding go ahead and weld the parts together. Otherwise, you should be able to take a piece of metal and drill holes to bind the legs to the frame.

Step 4: Supports

The supports for the desk will fold back inside the legs of the desk when folded away. For this reason, the supports must not be too long. Too short however and the supports won't hold. Solving for the boundaries was a fun break and involves only middle school level math. Feel free to try to think through a solution. It's a fun little word problem. I have outlined the boundaries. Since my table was 19 inches long and the legs 3 feet (36 inches long), I could make a support greater than 19 inches and smaller than 29.8 inches. I opted for a 2 ft (24 inches) support. We can now make two supports for the desk.

Step 5: Making Supports

Now its time to make the supports. Cut them to the appropriate length based on the previous step. The width should be based on the width of the legs (it should be able to rest inside the leg). If you have angled support, as I did, cut a maximum of 45 degrees on one side of each support.

Step 6: Attaching the Supports

You will first need to make a hinge for the supports. This should be the same width as the support/inside of the leg. Drill holes on both sides of the hinge and edge each of the support. When attaching the hinge to the support, attach it so that it closes on the outside of the support. To find where to drill the holes for the legs, rest the desk on a right surface as shown so that your hinge lies in the position it will be once assembled. Mark it and drill the holes in the appropriate place. Attach the supports to the desk.

Step 7: Paint, Install & Enjoy

Now all that's left is installing it. Paint the desk your desired color and allow it to dry. Make pilot holes in the legs and drill the desk to the wall. Having someone hold the desk flat against the wall while you drill can be helpful. Now, all that left is to set it up and enjoy! Raise the desk by pulling up on both supports until the desk locks into place. Bring up your favorite chair and set up an extension cord along the frame.