China Down The Hole Drilling DTH Hole Opener Button Bit

Hole openers are specialized drill bits that can be used to widen pre-existing size bore holes. At some work condition it may be necessary to increase the size of a pre-drilled hole to a larger diameter or to drill large diameter holes. Hole opener bits are designed specifically for this purpose, which is an effective way of enlarging holes, hence the bits named as "Hole Opener". A common practice involves drilling a relatively small pilot hole at first stage, and second and final stage then further widening it with a hole opener bits, since this can result in a straighter hole and require less powerful machinery. And different stages can be set per drilling specifications to maximize cutting breaking and removal, and rig capabilities. Besides, rotation torque, the DTH hole opener involves a concussive force that repeatedly impact a drilling head into the rock or other substrate. The impacting action can pulverize rock and also force it back and up, helping to clear out the borehole. So, in addition to widening a bore hole, a hole opener can also clean excess material out of it.
The drilling of large boreholes is required in a number of different industries, such as hydrocarbon exploration, well drilling, and horizontal excavation for tunnels and other purposes and so on. Drilling one large hole could require an exceptional amount of power and very large machinery, so the process is sometimes done in several steps. In some cases, a relatively small size bit will be used to drill a pilot hole. This kind of drilling practice typically requires less energy than doing it in one step and can also result in a straighter borehole. After this initial pilot hole has been drilled, a hole opener can be used to widen the borehole. In such case, the result can be a more precise borehole that was created with less powerful equipment than would have been needed to drill a large hole at beginning directly.
Specifications:
D(mm)D1(mm)GaugeFrontShank165821414DHD340
SD4
QL401789916141901151614DHD350
QL5021613816142541591614DHD360
SD6
QL60305208161638129616163052081616DHD380
QL8038129616164453051816SD10
NUMA10048231118166604451918SD12
NUMA120