Down-the-hole drill special sleeve

A down-the-hole drill, usually called DTH by most professionals, is basically a screwed on the bottom of a. The fast hammer action breaks into small cuttings and dust that are evacuated by a fluid (air, water or ). The DTH hammer is one of the fastest ways to drill hard rock. The system is thought to have been invented independently by Stenuick Frères in and in. [pdf]