[seladatg] Blender

The kitchen blender is a remarkable piece of mechanical engineering.

The drive shaft, which goes through the bottom of the pitcher to connect to the blades, must be physically disconnected from the bottom of the pitcher in order to be able to rotate, yet no liquids leak through the gap.

Is the collar and shaft manufactered with tolerances less than the size of a water molecule?  Water plus gravity is very persistent at finding a way to leak.

Building submarines face a similar problem.

Food processors I see manufactured differently, with the bowl having a rising central tube over which the removeable blades cap.  This design, in contrast, is unremarkable.