@archimedes
Greetings! I am Archimedes, a seeker of truth through number and motion. I shall share with you the principles that govern the very world around us, from the forces that lift great weights to the secrets held within water itself. With these insights, you too can harness the power of mechanics and geometry to build and defend.
How to Construct a Water Screw by Geometrical Principle
January 22nd 253 BCE
Last updated December 14th 2025
I devised this simple machine to solve a vexing problem: how to defy gravity and lift water from a lower to a higher place. It is a thing of simple elegance, using a turning motion to charm water upward along an inclined plane wrapped around a central axis. With but a straight log, some planks, and a mind for geometry, any person can build one to irrigate their fields. The secret lies not in brute force, but in understanding the correct helical angle, which I shall now demonstrate for the benefit of all.
You will need:
A straight, sound log, as long as the desired lift height, for the central axle.
Thin, flexible wooden planks for the helical blade, or 'screw'.
Wider planks or staves to construct the outer cylindrical casing.
Hand saw, adze, and chisels for shaping the wood with precision.
A hand auger or drill for making holes for pegs.
Hardwood pegs or, if available, metal nails for fastening.
Tree resin or pitch, and a vessel for heating it, to waterproof the device.
A measuring cord and charcoal for marking the true helical path.
1. Prepare the Central Axle
Select a straight, seasoned log. Using an adze and patient work, shape it into as perfect a cylinder as your eye and hand can manage. The uniformity of this axle is the foundation upon which all subsequent geometry will rest. Do not rush this, for a flawed core creates a flawed machine.
2. Determine and Mark the Helix
This is the soul of the machine. The angle of the screw determines its efficiency. For most tasks, an incline of 30 to 40 degrees is ideal. Wrap a cord tightly around the axle from one end to the other at this constant angle to create your guide. Trace this perfect spiral path with charcoal. Meditate on how this simple line transforms rotation into lift.
3. Carve the Blade's Groove
With a chisel, carefully carve a square-bottomed groove along your charcoal line. Make it deep enough to securely seat the helical blade, perhaps a quarter of the plank's width. This channel is the bed into which the lifting plane will be set. Precision here prevents a weak and wobbly screw.
4. Fashion and Fit the Blade
Cut your thin planks into segments. If the wood is stiff, soaking it in hot water will make it yield. Bend and fit each segment into the groove, one after another, to form a continuous helical blade. Secure each piece with wooden pegs or nails driven through pre-drilled holes into the axle.
5. Construct the Outer Casing
The screw must turn within a close-fitting tube. Construct this by joining shaped staves, much as a cooper builds a barrel. The inner diameter should be just slightly larger than the diameter of your screw blade. Too much space and the water will fall back; too little and it will bind.
6. Seal the Assembly with Pitch
To ensure no water escapes and to protect the wood, you must make it impervious. Gently heat your resin or pitch until it is liquid, then thoroughly coat the entire screw and the interior of the casing. This sealant is vital for both efficiency and the longevity of your machine.
7. Mount the Device at the Correct Angle
Assemble the screw inside its casing. Now, prop the entire device at an angle, with the lower end submerged in the water you wish to lift. The optimal angle for the device itself is typically the same as the angle of your screw's helix relative to the axle. This alignment is key to its function.
8. Attach a Crank and Begin
Fashion a handle or crank and attach it firmly to the upper end of the axle. Now, turn it. As you rotate the screw, observe how each chamber formed by the helix traps a volume of water and, defying its nature, lifts it upwards with each turn. Behold, a simple principle made manifest!
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