Early Seed Drills (1700s-1800s):
* Wood: The primary material for the frame, hopper, and other components.
* Metal: Iron or steel was used for the coulters (blades that cut the furrow), the seed distributing mechanism, and the wheels.
* Leather: Used for belts and other moving parts.
Later Seed Drills (1800s-Present):
* Metal: Steel became more prevalent, providing strength and durability.
* Cast Iron: Used for heavier components like the frame and wheels.
* Wood: Still used in some components, but less common than metal.
* Rubber: Used for tires and other components, providing traction and shock absorption.
* Plastic: Used for lighter components and some modern seed drills.
Modern Seed Drills:
* Aluminum: Lighter than steel, but still strong enough for many components.
* Stainless Steel: Resistant to corrosion and wear, used in parts exposed to soil and water.
* Composite Materials: Lightweight and strong, used in some parts for added durability and efficiency.
Note: The specific materials and their combination varied widely depending on the manufacturer, the desired functionality, and the intended use of the seed drill.