Jethro Tull (agriculturist) the seed so that it could grow. Before the introduction of the seed drill, the common practice was to plant seeds by broadcasting (evenly throwing) them across the ground by hand on the prepared soil and then lightly harrowing the soil to bury the seeds to the correct depth. In his 1731 publication Tull described how the motivation for developing the seed-drill arose from conflict with his servants. He had struggled to enforce his new methods upon them, in part because they resisted the threat to their position as labourers and their skill with the plough. Jethro Tull invented some
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