Drilling through unconsolidated ground conditions in order to set casing into bedrock is one of the most challenging tasks facing the drilling industry. That is why Numa has spent so much time and energy designing a drill bit that can drill a larger diameter hole than the casing, while simultaneously advancing the casing.
The Super Jaws® Overburden Bit is a under-reaming bit design with wings that extend out larger in diameter than the casing while in the drilling position. The face design of the Super Jaws® Overburden Bit keeps it almost identical with a conventional bit face, allowing for unmatched penetration rates and smooth operation while drilling through overburden, boulders, or bedrock. When drilling is completed, the bit is simply lifted off bottom, causing the wings to retract back into the guide body. This allows all tooling to be extracted while leaving the casing in place. There is no forward or reverse rotation required, nor any expensive rings left in the hole.
The Super Jaws® Overburden System is offered in two versions. One version utilizes an inexpensive drive shoe that is welded to the front of the casing. As the bit advances through the formation, the casing is advanced at the same rate due to the drive shoulder on the guide body contacting the drive shoe welded to the casing. The second version is called Super Jaws® ND, which stands for "No Drive" shoulder.