Pilot Bit                                                        Ring Bit                                                                                        Assembly

Application Range
      It is recommended to drill in rock formation where contains some ovals and fractures.

Outstanding Advantages
      The stable and reliable working performance and the less vibration of drill rig.

Different Structures
      Concentric system with ring bits, with wings and with blocks.

1.Operation Procedure of Permanent

1.When the drilling starts, the pilot bit drive the ring bit down to the hole, followed the casing shoe and casing.
2.When arriving the bedrock, reverse rotation of the tools and pull the pilot bit out from the hole, leaving the ring bit in the hole.
3.Pour the concrete or do the next construction work.

2.Operation Procedure of Retrievable

1.When the drilling starts, the pilot bit drive the ring bit down to the hole, followed the casing shoe and casing.
2.When arriving the bedrock, reverse rotation of the hammer and pull the pilot bit out from the hole,leaving the ring bit in the hole.
3.Pull the casing tube out with the ring bit and at the same time pour the concrete.