Mechanical piston drills employing hooked up bits on drill rods and going up and down like a piston inside a cylinder date from 1843. In Germany in 1853 a drill that resembled contemporary air drills was invented. Piston drills ended up superseded by hammer drills run by compressed air, and https://caidenmftgr.thechapblog.com/35558913/5-easy-facts-about-interest-rates-described