Need help with a toy chest/corner seat

[Ryan Swanson]

I am working on a corner seat which will have a toy chest style lid opening.

Of course, being my first time doing something like this, I've made a few mistakes in engineering and here is what I have right now.

My problem came into play when I decided to have a the top hinge joint about 4 inches away from the wall, instead of hinging flush with the back of the box. Thus, the back edge of the lid, where all weight will be supported, is floating in air.

I fashioned diagonal braces as you'll see here (this is all dry fit) that support each of the corners of the lid, but there is still sag in the center when supporting weight.

Any ideas as to how to solve this? The only things I can think of are to install a false back that the entire edge of the lid rests on, but of course I lose about 5 inches depth in the box volume. Otherwise, I could install a perpendicular piece at the center of the span that extends the 5 inches toward the front and gives a single point of support, but then I have a weird floating piece of plywood inside the box....which is strange (option 3, but not really considering this one if I can avoid it, is to add a full partition, but then I have very small spaces in the toy chest).

Please help!

Thanks!

http://i11.photobucket.com/albums/a184/siznimper/IMG_8446.jpg
http://i11.photobucket.com/albums/a184/siznimper/IMG_8447.jpg
http://i11.photobucket.com/albums/a184/siznimper/IMG_8448.jpg
http://i11.photobucket.com/albums/a184/siznimper/IMG_8385.jpg

[Lee Schierer]

First of all use a piano hinge all along the lid. This will transfer the weight to the back board. Then if needed attach a piece say 3/4 x 2 to the under side of the back strip just behind the hinge such that the 2" dimension is vertical. This will significantly stiffen the back edge. You could also attach cleats along the sides of the opening that stick out about 1/2 to 3/4" under the lid for added support along the sides. These supports for the lid should be glued in place.