The design and construction of these bins was a very complex affair as you can see from the drawings.The design was mainly to achive an aesthetic goal, I had not accounted for the weakness of the bins when picked up by the top few pices of wood. As it turns out the glued joints, between the pieces which make the bin, are not strong enough to support the weight of a full bin and tend to brake off when it is lifted this way. My brother has strengthened his with additional pieces screwed down the corners and it has not broken.