Blast Hole Drill - Gill Rock Drill Company, Inc.
2008-5-22 · DTH hammers, with the piston in the hole, tend to drill straighter holes at greater depth as compared to OTH drifters. The air-driven piston hammer causes the bit to rapidly impact the rock while the bit is slowly turned. DTH hammers are efficient in hard-rock types. With the hammer in the hole, drill-pipe vibrations are eliminated.Get Price