The
components
Driver bit
The driver bit is the device that transfers impact and rotation to the crown bit for drilling. The driver bit locks into three flats on the casing crown and they act together as a standard drill bit, both the driver bit and the crown have tungsten carbide buttons. The Driver bit drills with the crown advancing the casing to the desired depth. Afterwards the same driver bit can be used for sub-casing drilling.
Crown Bit
The crown bit is a two-piece unit permanently connected together. The upper part is welded to the casing, and the lower part, which has Tungsten Carbide is free to rotate with the driver bit.
- Impact zone: Direct energy from the hammer is transferred to the crown bit through three (3) recesses formed by the locking surface.
- Three (3) big air holes are drilled in the face of the bit (drilling end). Those holes are directly connected to three (3) large flushing air ways, this transfer the drill debris from the drilling end of the driver up in the casing. To help the evacuation of debris, three (3) smaller air holes in the flushing air ways, gives the cuttings some velocity