plywood archimedean screw water pump

This is an archimedean screw water pump made out of thin plywood and resourcinol formaldehyde glue

It is made like a christmas decoration, the center is made of a wooden space frame covered with plywood.
The stress is concentrated at the top in the middle, so this bit has to be made stronger than the rest.
This animation shows how water is carried up by the pump

This shows how to glue two plywood disks together; more disks, longer pump. After glueing the disks together they should be held in a jig while the center is inserted and the outer cover formed.

Although the disks are glued together flat, they have to be stretched in order to form the archimedean screw. They have to be held in this form while the pump is completed.
The pump is turned by means of a solid post along the middle; this must be a good fit in the centre space frame to prevent stress concentration. My pump used metal end fittings and plumber block bearings.
This is a design by Jeff Bindon available from him as a kit:

it is uncannily similar to the very first model archimedean screw I made, although his one works. My one didn't.
This is another one of his kits

If you have a low-melt glue gun & lots of styrofoam cups it's possible to make a screw pump by cutting the bottoms off lots of cups at the same shallow angle (use one as a pattern) then glue them all together with a slight rotational offset on each one so they don't just go round in a circle.
Someone (Daryl Adams) sent me this picture recently


made me wonder could you make one by modifying a standard length of plastic pipe by glueing plastic sections to the inside of it.


This is a pump that can be made by children:



This is another pump which can be made by children by glueing two drinking straws together with a third, short section across the top