Well, it took a little longer than expected, but here at last are the detailed insructions for the bed project, which as of tonight, is finished!!!
OK, after you spend most of a day getting your supplies together (you can expect to make at least two or three more trips to Home Depot to go back for all the stuff you forgot to get the first time around), the first step is to cut your side boards to length. For this project, the bed needed to fit a king sized mattress, so I measured the mattress to make sure everything would fit exactly - add about a half inch to each measurement so there is a little gap to help with making the bed. In this case, the two side rails measured 81" each, and the headboard and footboard measured 78" each.
Now normally at this point I would slap in a couple of screws because I'm the impatient type and can't wait to see how it's all going to look once it's put together, but it is much better to take a deep breath and sand each piece lightly and stain it at this point. That way there aren't any cracks that the stain can't penetrate, plus it's easier to work outside where there isn't as much dog hair waiting to stick to your wet stain. I chose Minwax stain in cherry and only applied one coat. Fortunately it dries pretty quickly, because the wind kicked up later and coated all the freshly stained boards in dust!
The legs are next, and this is the tricky bit, although you could make it easier on yourself if you want to. The posts for the two front legs should be cut to 14 3/4" each. I wanted the front of the leg to stick out 3/4" in front of the rail and come up 4" from the bottom of the rail, so you need to cut a notch in the post starting 3/4" back from the front face of the leg, and extending 4" down into the post. If you wanted to take the easy way out, you could just make another cut at 90 degrees to this one, making a simple notch for the rail to sit on. Since we wanted to make it extra strong, however, we cut a 3/4" notch to sandwich each side of the rail, with the back side of the notch 3" higher than the bottom of the notch (it had to be lower than the front side so it wouldn't interfere with the mattress). This part was a pain in the rear end, since it required the use of a chisel to chip out the notch. The end result looked like this:
The posts for the headboard were already cut at 36". Again, you could just screw them to the rail, but that would be far too easy. If you're pretty handy with your tools and want to make the whole thing stronger, make a notch in the post for the post to fit into. Measure up 10 3/4" from the bottom of the post, and cut a groove 1/2" deep across the post with the table saw. Cut another groove 7 1/4" higher to accomodate the size of the rail, and use a router to cut out the wood betwen the grooves, forming a notch 1/2" deep.
After that, line up all of the posts by the bottom of the notches and trim a tiny bit off the bottom of all the legs to make sure they are all exactly the same length.
Next, cut your 2x2s to approximately 75" each and screw these onto the back side of the 81" rails, 2 3/4" from the top of the rail. These will form the cleats on which the slats will sit. You could make the cleat lower if you want the mattress to sit further down inside the frame.
After sanding and staining the posts, it's time to give up for the day, because it's getting dark outside. And because it's still dark by the time you get home from work, over the next week you'll need to move everything inside, where at least you can watch movies on Netflix while you figure out the exact placement of the bed hangers which will fasten the rails together.
Bed hangers are fantastic. I found them at a woodworking supply place, but you can also order them online. They allow you to clip the sides of the bed together, form a tight and strong joint with no visible screws and to easily disassemble the whole thing. Unfortunately they don't come with instructions, or these didn't anyway, so it took a couple of tries to figure out the best way to do it.
Next, screw on the legs, which should be 8" from each corner. Don't skimp on the hardware unless you want the bed collapsing on you in the middle of the night - we used heavy duty screws and plenty of them. Stand back, and do a happy dance, because progress is finally being made!
Don't get too excited, though, because now you need to apply at least two coats of sealer. I used hand rubbed polyurethane in a satin finish, which is one of my favorite finishes since it's durable, easy to apply, doesn't show brush strokes, and dries quickly. Wait some more until everything has had at least 24 hours to dry, and then move the whole thing into the bedroom.
Now you need to add the center support. Use the offcuts from the 2x2s you used for the side cleats to make two more small cleats in the center of the headboard and footboard, 4 1/4" from the top of the rail. Screw a 2x4 cut to 80 3/4" long into these cleats. If you measured everything right, the top of the 2x4 should be 2 3/4" from the top of the rail, level with the side cleats. Finally you're ready to add the slats. We ended up using 15 1x4s cut to 77 3/4" each. Screw these into the cleats on the side and the center support, spaced 2" apart.
I didn't want to screw on the headboard until the mattress was in place so I could see how high it should be. In the end the board for the headboard was screwed in so that the top of it is 3" higher than the top of the posts. That makes it just high enough to provide head support but not so high that the pillows can slip out onto the floor.
Stand back, congratulate yourself on a piece of utterly brilliant planning and execution, and count all the money you've saved. More importantly, enjoy a full night of sleep without involuntarily rolling into the center of the mattress once.
I'm really pleased with the finished result. It is solid and level, and looks like a nice piece of furniture. On reflection, I might have made the legs just a little bit shorter, but I'm not at all unhappy with the overall height. There is actually a lot more space underneath now that the box spring is gone. Overall, I think the whole thing turned out really well.