Suman Tools breast drill Machine can be used to create holes of various sizes in wood and other materials. Suman tools drills are generally powered by hand cranks, and they have a breastplate which allows the operator to lean over the drill and bear down with his weight. This ability to force weight down into the drilling process makes the breast drill more capable of performing heavy jobs than most other hand drills. It also means that the operator doesn't have to use as much energy while using the drill. Essentially, the drill is allowing the worker to capture the energy of gravity, which is constantly pulling his weight towards the earth, and use it to make his work easier.