Roller Cone Bit
A roller cone bit is a tool used in both oil drilling and offshore drilling in the petroleum industry to crush rock in a very efficient manner while incurring minimal wear and tear to the tool's cutting surface. The roller cone drill bit, invented by a man named Howard Hughes, is designed with conical-shaped cutters with multiple spike teeth on them.
 How it Works
As the drill string rotates, the bit's cones roll along the bottom of the hole in a circular fashion. As the cones roll, new teeth come into contact with the bottom of the hole, instantly crushing the rock below and surrounding the bit tooth; other teeth are automatically lifted off the bottom of the borehole. A high-velocity jet of drilling mud is used to remove the rock chips at the bottom and bring them up to the surface. While this happens, another tooth of the roller cone bit makes contact with the bottom of the borehole to create new rock chips. The entire process gets repeated. The teeth on a roller cone bit are also designed to intertwine with the cones to clean them and enable larger teeth positioned on the bit to be used.