The outer part of this tray frame was joined with two stacked 15mm metal wedges towards the back, and three in the middle, for added strength a dovetail key was also used on the inside, with lots of Titebond glue. The backing frame has also been a little over engineered; with crossbars and supports at the corners, but at this size I would rather go a little over the top than make something flimsy that starts to pull apart as it is moved around and handled. The backing frame was glued into the rebate of the main frame and fixed in place all round with nails.
