King Bed Plan Help

With just pocket screws, I wouldn't trust it either, I don't think. If you mortise the bottom (foot of the bed) rail into the two feet, you could attach the side rails with something like this at the head and foot. That would probably last quite a while.

Just some ideas,
Acer

A king bed is a double twin in size. What that implies is that the slats have an 84 inch span.

If you remember from High School Physics, just a slight bend in the slats puts an extraordinary pulling pressure on the ends of the slats.

The suggestion here is to build the external aesthetics to please your wife but build the mattress support as a platform bed. You won't need a box spring and you can use a softer mattress but still have nice firm support.

Just make sure that you don't have wood on wood pieces moving and squeaking. You don't want the neighborhood aware of what you're doing.

Make the rails knock-outs like Acercanto suggested. I personally can't stand sleeping on beds that don't have box springs or a solid floor under them so I never recommend going without a full platform, especially on a mattress as heavy as a king size mattress is. That said, I would definitely build a center leg/rail as well because a full span without one simply won't hold up. You'll collapse the bed the first time you get "frisky" if not the first time you simply sit on it.

I'd probably build the slats as two torsion boxes that then attach/sit on the rails with just a single center leg under the inside long edge of the torsion boxes. Easy to knock down, when the time comes, but very strong. I'd also likely add in some under bed storage drawers, but that drastically changes the design.

If I were building that, I just build the headboard and buy a steel frame to fasten to it for the bed. The rails and feet won't show on that design anyway, so you don't loose anything, and you gain a bed that's easily broken down. Plus, most of those frames are on wheels, so you can roll the bed around for cleaning (fair warning: it rolls, but nor so easily).

Thanks for the replies guys! I found another plan which makes some improvements on the original - here it is. http://www.jrlwoodworking.com/2013/06/furniture-plans-ana-white-inspired.html. Now I have another question - If I wanted to attach the footboard rail to the front legs with a mortise and tenon joint, would the jessem pocket mortise mill be up to the task? I would be attaching a 2x10 board to a 4x4 post. Here is a link to the tool if you haven't heard of it - it looks pretty cool. http://www.jessemdirect.com/Pocket_Mortise_Mill_p/08200.htm. I would then use the brackets from Rockler to attach the side boards to the headboard and footboard. Thanks for the help!