This instructable is for a simple queen sized (60"x80") bedframe made from 2x4's. To make the same for a double or single bed you'd just have to re-size it, you might also be able to omit the centre support and feet for a smaller bed. I had a boxspring to go under my mattress but you could also use some 1x4's if you don't have one.

Step 1: Collect Materials and Tools

Materials:

8x 2x4's
~46x long screws (I used 2.5" deck screws)
glue
wood finish (stain, paint, clear coat... whatever you'd like! I used some red wood stain and polyurethane)

Tools:
router with 1/2" roundover bit
drill with 2 bits, one to drill pilot holes for your screws, and one to drive your screws
circular saw
random orbit sander and/or sandpaper
measuring tape
pencil

alternative tools:
You could use a spokeshave, plane or just sandpaper instead of the roundover bit on the router. you just need to do something so the edges of the boards aren't sharp after assembly.

The circular saw could be replaced with any kind of crosscut saw, it wouldn't be too hard to just use a hand saw for all the cuts required.

Step 2: Cut Pieces to Length

Using your Saw crosscut your 2x4's to length. You should end up with 16 pieces. Cut the feet last so you can use up any extra length you have after cutting the long pieces.

Cut list:

9x 12" (feet)
4x 80" (side pieces)
2x 63" (ends)
1x 83" (middle piece)

Step 3: Notch End Boards

Next you need to make a notch in the center of both 63" long end pieces. This lets them sit on the middle support beam. The notch needs to be just big enough for a 2x4 to fit in, the easiest way to mark it out is to measure 29 3/4" from one end of the board then trace a small piece of 2x4, like one of the feet. Once it's traced check that the other side of the tracing is also 29 3/4" from it's end. You could also mark 29.75" from each end across the board then make a rectangle 1.5" from one edge between the marks.

You can make the notch any way you'd like. I cut 1.5" down at both my marks then used a chisel between the marks to knock out the notch. It works easiest if you start close to the edge and work backward towards the line. You could also do it with a dado stack on a table saw or using a router. The notch doesn't need to be perfect, it just needs to fit the center board.

Step 4: Attach Feet

Next up is to attach the feet. It doesn't really matter where you put them, but I would suggest putting them at least 8-10" from the ends of the boards so it's harder to stub your toes on them. To put the middle foot on each board just halve the distance between the outside feet and mark 6" to either side of the center and you'll have the spot for your feet.

Using my little work-mate the feet clamped on edge with a bit sticking out. the long boards could then be set on top of it to screw together. This made it hard to see where the foot was so I slid some thin scrap wood on either end of the foot so I could see where it was with the board on top. I marked another thin piece with a mark where the edge of the top board should be so the foot is centered.

Put some glue on the edge of the foot, then place the top board on top in the right position, drill a couple pilot holes, then screw the pieces together and move on to the next foot.

It sounds more complicated than it is, you can even center the feet just by feel and I doubt anyone would ever notice if they're off center a bit.

Remember that the middle board (83") is longer than the edge pieces (80), so if you make your feet 10" from the end of each edge board they need to be 11.5" from the end of the middle board.

Step 5: Add Side Rails

The next step is to add the side rails to your edge pieces, these are so your mattress doesn't slide side to side off the bedframe. Put some glue along the edge of your side pieces that already have feet on them, line up the rail so it makes a sideways "L" shape, then drill pilot holes and screw just like the feet.

you should have 5 parts now:

2x 80" footed and railed side pieces
2x 63" notched end pieces
1x 83" footed middle piece

Step 6: Soften Edges

Next, it's important to soften all the edges of your pieces. I missed softening the end grain edges of the notched pieces, and if I ever hit my foot on the bedframe that's always where it happens =P

I used a 1/2" roundover bit in an electric router to soften the edges but you could do it with all sorts of tools, even just sandpaper. You don't need to go all the way to 1/2", just enough that you're not going to get slivers or anything from them.

Step 7: Apply Finish

Next up is to apply whatever finish you'd like. I used some red wood stain then clear polyurethane. Just follow whatever instructions the finish you want has. I would definitely suggest letting the finish dry for longer than you think is necessary before assembling and using it. It's going in your bedroom so any leftover odours can be very noticable!

Step 8: Assemble

The final step is to assemble your bedframe and use it!

The easiest way to assemble it is to:
1) set your notched boards with the notches facing up
2) set the 83" long center board into the notches with the feet facing up, drill/screw in place (2x screws per end)
3) flip the assembled parts over so it is now sitting on the feet
4) place the side pieces between the end pieces one side at a time. drill/screw through the end pieces into the end grain of the side pieces (2-3 screws per end) make sure you put at least one screw in each long board of the end pieces
5) place boxspring and mattress into bedframe, and make your bed! you're finished!!!

So far it's lasted 4 years, been assembled and disassembled multiple times, moved cities and it's still going strong!

Step 9: Modifications

If you don't have a boxspring you could cut some 1x4's to 60" and place them in the bedframe before your mattress. The rails are tall enough that there shouldn't be any problems

I bought some felt shoe insoles from the dollar store to place under the feet so there's no chance they can scratch the floor. I cut each insole in half and stuck them to the feet with loops of packing tape