Wes wrote:

(...)

After a while working on another project I realized what was going on. I have a bowl with
ramps heading up hill in a spiral. On the bottom there is a plate that an electro magnet
that is grabbing and releasing every 1/60 or 1/120 of a second. The leaf springs are
ground to bring the bowl to resonance at the period of the magnet. The leaf springs are
inclined so that when the bowl is drawn to the magnet, the bowl rotates counterclockwise
and goes down, falling from under the fasterners. when the magnet is de-energised the bowl
rises, contacts fasteners and moves them ahead as the bowl rotates clockwise.

That was one of the half-million things I never understood.
It bugged me for years. Now I 'got it'.

Thanks Wes.

--Winston