I built this storage unit to hold 9 standard Meccano cases using dressed pine 19mm thick by 290mm wide. The shelves are 430mm wide and the sides are 1020mm high. This gives a space for 3 cases on each shelf. It was fairly straight forward to make. Go to your hardware store and ask them for a 4 metre length of dressed pine 19mm x 290mm. This is a standard size in Oz. Ask them to cut it thus.. 4 lengths at 430mm for the shelves and 2 lengths at 1020mm for the sides. Clamp the sides down on a work bench and glue the 4 shelves between them. After clamping and making sure it's all square (see photo in comments) mark the spots for screws and drill the holes to prevent splitting, then screw the shelves in. I used square head decking screws 8g x 40mm.