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 panel work. The finished hole can often be made quite smooth and burr-free, especially in plastic. An additional use of unibits is deburring holes left by other bits, as the sharp increase to the next step size allows the cutting edge to scrape burrs off the entry surface of the workpiece. However, the straight flute is poor at chip ejection, and can cause a burr to be formed on the exit side of the hole, more so than a spiral twist drill bit turning at high speed. The unibit was invented by Harry C. Oakes and patented in 1973. It