I have some leftover piece of 12mm OSB. I want to make this stool out of it: Originally it was made from 18mm plywood, obviously I need to adjust to use thinner board. I want to keep the weight to the minimum, and keep the strength (I'm going to stand on it occasionally to reach high shelves).
2) How should I join the corners? Original screws to the edge seems unreliable for a thin board. I'm thinking screws to aluminum angle bar.