DTH Hole Opener Reaming Bits 80mm - 445mm Guide Diameter

The ROSCHEN DTH Hole Opener Reaming Bits are purpose-built for enlarging existing pilot holes in hard rock formations. Designed for water conservancy dam foundations, bridge pile sockets, large-diameter water wells and geothermal borehole enlargement, these bits deliver efficient reaming with excellent hole quality and diameter control.

Technical Specifications

Design Features

• Drop Center Face Design: Optimized for reaming applications with aggressive cutting geometry that maintains penetration rate through variable rock hardness
• Radial Flushing Grooves: Deep radial channels combined with multiple lateral flushing ports ensure rapid cuttings removal, preventing bit packing in large-diameter holes
• Heavy-Duty Gauge Protection: Double-row spherical carbide buttons on gauge surfaces maintain precise reamed diameter throughout the bit service life
• 42CrMo Forged Body: High-toughness alloy steel with deep case hardening withstands the high bending loads typical in reaming operations
• Anti-Sticking Profile: Tapered body design with polished surfaces reduces friction against borehole walls, preventing stuck-bit incidents

Application Guidance

For optimal results, drill the pilot hole 10-20% larger than the guide diameter to ensure smooth bit entry. Maintain air pressure at the upper end of the hammer operating range during reaming for maximum flushing efficiency. Recommended rotation speed: 20-35 RPM for diameters above 254mm to prevent excessive gauge button wear.

Custom Sizing Available: Need a reaming diameter that is not listed in our standard range? Our engineering team designs and manufactures custom hole openers to your exact pilot and target diameter requirements.