The parts consist of a pilot bit with big internal flushing holes and exterior flushing grooves that work together as one effective drill bit. Ring bit (reamer) that is symmetrical and has an internal bayonet connector the shoe used to drive the casing. Any standard DTH hammer shank or top hammer rod thread is used to attach the pilot bit.
Symmetric Casing is a system comprised of an ingeniously simple concentric method of drilling through overburden with casing. Symmetric Casing can drill straight holes at any angle (including horizontal) and to depths beyond 100 meters.
The Symmetric Casing shoe is welded to the casing. The pilot bit and ring bit are locked together by the bayonet coupling. They drill a hole large enough to allow the casing to be pulled into the hole. The pilot bit and ring bit rotate with the drill string while the casing shoe and casing do not rotate. When the required depth is reached, the pilot bit is unlocked by a slight reverse rotation of the drill string.
The Symmetric Casing shoe is welded to the casing. The pilot bit and ring bit are locked together by the bayonet coupling. They drill a hole large enough to allow the casing to be pulled into the hole. The pilot bit and ring bit rotate with the drill string while the casing shoe and casing do not rotate. When required depth is reached, the pilot bit is unlocked by a slight reverse rotation of the drill string. The drill string and pilot bit will be retrieved through the casing, the ring bits and casing shoe will be left in the hole for permanent casing system. Also the ring bits and casing can be retrievable through the special design for ring bits and casing shoe. We can manufacture both permanent Symmetric and Retrievable Symmetric Casing which can meet your comprehensive requirement.
The full face head design of the driver rock drill bits, along with a satisfactory ring or reusable ring, greatly increases drilling penetration rate and hole straightness. A good seal is provided to the button of the drilling hole by the internal flushing grooves and the built-in casing shoes, reducing disturbance to the area around the drill hole.
