Brief description

A watermill is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering. Such processes are innovative for agriculture and manufacturing.

Use / Function

• Milling: Grinding grain into flour.
• Sawing: Powering large saws to cut lumber.
• Fulling: Pounding woolen cloth to clean and thicken it.
• Metalworking: Powering bellows and trip hammers in forges.
• Scale: Industrial/Local.

Operating principle

The mill harnesses the kinetic energy of flowing or falling water.

1. Flow: Water is directed onto the blades or buckets of a water wheel.
2. Rotation: The force of the water causes the wheel to rotate.
3. Transmission: The rotating shaft of the water wheel is connected to gears that change the direction or speed of rotation.
4. Work: The final gear or shaft drives the machinery (e.g., rotating the upper millstone).

How to create it

1. Site selection: Find a source of flowing water with sufficient volume and drop (head).
2. Water Wheel construction: Build a wheel with paddles (undershot) or buckets (overshot) made of durable wood or metal.
3. Sluice/Millrace: Construct a channel to direct water from the source to the wheel.
4. Drivetrain: Install a main shaft connected to the wheel and use bevel gears to transfer power to the vertical shaft of the mill.
5. Millstones: Set up the fixed bedstone and the rotating runner stone.
6. Control mechanism: Install a sluice gate to control the water flow and stop the mill.

Materials needed

• Water wheel and structure: Strong, water-resistant wood (like oak) or iron.
• Millstones: Hard, abrasive stone (granite, basalt).
• Shafts and Gears: Iron or hardwood.
• Lubricant: Animal fat or grease for the bearings.
• Binding: Nails, bolts, and metal bands.

Variants and improvements

• Undershot wheel: Placed in a fast-flowing stream; water passes underneath. Simple but less efficient.
• Overshot wheel: Water is fed from the top into buckets. Much more efficient but requires a significant drop in height.
• Breastshot wheel: Water enters at the middle of the wheel.
• Water Turbine: Modern, high-efficiency version used for electricity generation.

Limits and risks

• Water Dependency: Seasonal changes (drought or freezing) can stop the mill.
• Flooding: High water levels can damage the structure.
• Maintenance: Constant exposure to water causes wood to rot and iron to rust. Millstones need regular dressing.
• Safety: High torque machinery can be extremely dangerous if contacted during operation.