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 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