British Agricultural Revolution far apart. Alternately seeds could be laboriously planted one by one using a hoe and/or a shovel. Cutting down on wasted seed was important because the yield of seeds harvested to seeds planted at that time was around four or five. The seed drill was introduced from China to Italy in the mid-16th century where it was patented by the Venetian Senate. Jethro Tull invented an improved seed drill in 1701. It was a mechanical seeder which distributed seeds evenly across a plot of land and at the correct depth. Tull's seed drill was very expensive and fragile and therefore
Drill bit application. Many hard materials, such as carbides, are much more brittle than steel, and are far more subject to breaking, particularly if the drill is not held at a very constant angle to the workpiece; e.g., when hand-held. General-purpose drill bits can be used in wood, metal, plastic, and most other materials. The twist drill bit is the type produced in largest quantity today. It comprises a cutting point at the tip of a cylindrical shaft with helical flutes; the flutes act as an Archimedean screw and lift swarf out of the hole. The twist drill bit was invented by