76mm Symmetric Casing System by Top Hammer

  • Casing O.D.: 76mm
  • Casing Wall Max: 8mm
  • Ring Bit I.D.: 41mm
  • Ring Bit O.D.: 84mm
  • Pilot Bit O.D.: 59mm

76mm Symmetric Casing System by Top Hammer-ProDrill

Rock drilling tools manufacturer ProDrill: Symmetric drilling system is designed to drill and case a hole simultaneously through unstable ground conditions. The driver bit incorporated with a satisficial ring or reusable ring makes a full face head design which significantly improves the penetration rate and hole straightness of drilling. The internal flushing grooves together with the built-in casing shoes gives a good seal to the button of the drilling hole, and thus minimizing the disruption of the surrounding of the drill hole.

RoBit SOD 76 Symmetix Casing System with rock drill bits: Ring bit and Pilot bit by Top Hammer
Application Range: Suitable for drilling water wells, geothermal wells, medium mini-type grouting hole of building, dam,tunnel umbrella and harbor project.
1. Ring bit and casing shoe assembly is welded to casing prior to drilling. Lock the assembly into pilot bit with hammer. The pilot bit’s upper shoulder engages the shoulder of the casing shoe.
2. Hammer’s percussive energy is transferred through the pilot and ring bits, crushing rock. Part of impact energy advances casing.
3. On completion of drilling and casing, the drill string with pilot bit is retrieved by a slight reverse rotation to unlock the bayonet coupling. The ring bit stays in the hole, and can be recovered only if the casing is retrieved.
4. Drilling continues to the desired depth in the bedrock using a conventional drilling.

Concentric Casing System by DTH Hammer Technical Data:

76mm Symmetric Casing System by Top Hammer-ProDrill

Symmetric Overburden Casing System:

76mm Symmetric Casing System by Top Hammer-ProDrill




Forepoling,also known as tube umbrella,tunnel umbrella, is an application used to strengthen tunnel roof in broken rock condition.Drilling system consists of casing tubes which are drilled through the overburden as an umbrella and filled with grouting.ProDrill symmetric casing system allows easy driving of the casing tubes into the ground with low torque demand.

ProDrill symmetric casing overburden drilling system mostly used in forepoling are ProDrill+88,9/8, ProDrill 114,3/10,and ProDrill 139,7/10.

76×6.35symmetric casing system drawing

Casing System by DTH Hammer:

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