If you have some relatively small boxes next to each other you can pinch them with your fingers and lift them vertically. I would like to do this with big boxes, but I don’t know how to calculate certain things. I would like to make a frame with 4 plates on it which pressure the boxes horizontally so they can be picked up vertically. (Most likely I will also put a plate under the boxes to support but let’s pretend I will not). Picture: Assume there are 25 boxes (5x5) and they weight 150kg total. How to calculate the pressure needed to be able to pick up all the boxes vertically with the horizontal pressure provided by the cylinders? Assume there is also no acceleration and the boxes only have to be pinched so they can be picked up and they won't fall. Friction coefficient box on box μs = 0,5 0,5 Friction plate on box μs = 0,4 I know it’s impossible to exactly calculate it because of the many, many other factors. But all help would be appreciated.