Gridfinity divider bins with magnetic stacking

For low-quantity/small parts storage I wanted something that would stack at least a bit securely. I tried a few approaches and ended up with this design that adds an extra magnet on the bottom and a pillar in the middle of the bin with a metal screw. The force of a single magnet is enough to hold up a stack of 3 bins filled with parts, as long as you don't shake it around too much. There's also a lid with built-in magnet to close off the top bin and prevent small parts from escaping.

There are 1-, 2- and 4-compartment variants in both 2U and 3U height (6U versions don't make a lot of sense for stacking). 

The best screws to use in the central pillar is an M3x6mm hex head countersunk screw (as shown in the last photo), which provides the largest contact surface with the magnet.

NOTE: This mechanism is not suitable for mobile/portable/traveling use. The magnets are not strong enough to hold everything together when a stack gets shaken around.