Integral Bullnose Hole Opener

Atlas Rock Bit Integral Bullnose Hole Openers are built strong from a solid casing to withstand the high torsional loads of pilot hole enlargement.

The single piece integral body eliminates a threaded or stubbed bullnose to maximize strength.

The full length pilot, available in a variety of lengths from 30 to 42 inches, centers in the hole to minimize side tracking.

Field-proven quick-change cutter assemblies offer a wide range of cutting structure s from tooth type for soft formations to insert type for hard abrasive formations.

The cutters are interchangeable to provide flexibility for use in any formation.

Cutters may be changed quickly and easily on the rig floor.

For improved hydraulics and greater penetration rates all bodies have regular (cutter pocket) circulation. C-12 and larger bodies are also available with wing circulation. Simple nozzle retention system enables quick and easy changeout.


  • Integral body for maximum strength.
  • Hardfacing for longer life and extended wear.
  • Interchangeable cutter types for soft to hard formations.
  • One-piece body eliminates threaded or stubbed bullnose.
  • Available without bullnose circulation. (Bullnose with circulation incorporates replaceable nozzles.)

Cutter Types

Type S

Tooth type for soft formations such as shale, sand, sandstone, red bed and soft limestone.

Type M

Tooth type for medium formations such as shale, sand, lime, and shaley lime.

Type H

Tooth type for medium hard formations such as lime with chert streaks, dolomite, and sandstone.

Type H8

Insert type for hard abrasive formations such as sandy lime, sand, cherty granite and quartzite.