Down-the-Hole Drilling Tools

DTH Drill Bits

Carbide-button bits for down-the-hole hammers in flat, concave, convex and drop-centre face designs. Shank type ties the bit to the hammer, and face design to the rock.

Features

  • Shank type is hammer-specific, so a bit diameter alone is never enough to order against.
  • Concave faces improve hole straightness in variable formations; flat faces give the highest penetration in uniform rock.
  • Gauge buttons control hole diameter, and gauge wear is what takes a hole out of specification.
  • Spherical buttons in hard abrasive rock and ballistic buttons in medium rock is the usual starting point, then adjusted from observed wear.
  • Foot valves and blow-tube condition in the bit affect flushing as much as the hammer's air supply does.

Specifications

Figure Typical range Unit Why it matters
Bit diameter 85 - 254 mm Set by the hole design and the charge diameter.
Face design flat / concave / convex / drop centre Trades penetration against straightness for the formation.