Mechanical piston drills using hooked up bits on drill rods and relocating up and down like a piston inside of a cylinder date from 1843. In Germany in 1853 a drill that resembled contemporary air drills was invented. Piston drills were superseded by hammer drills run by compressed air, as https://preciousmetalstrading95059.angelinsblog.com/35713320/the-market-volatility-diaries