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 four 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 a pilot hole below the crown to guide the direction of the casing in rough drilling. Afterwards this pilot space below the crown allows the square bit to turn without touching the crown.
- Impact zone: Direct energy from the hammer is transferred to the crown bit by way of two (2) recesses formed by the locking surface plus another contact zone all around the periphery of the driver (donut).
- Evacuation: Two (2) big air holes are drilled in the face of the bit (drilling end). These holes are directly connected to two (2) larger flushing air ways that enables the drilled debris from the drilling end of the driver to be up through the casing. To help the evacuation of debris, two (2) smaller air holes in the flushing air ways are added to generate added velocity help evacuate the cuttings.
This model also comes with a “rotational-crusher zone”. This protective zone is placed at the end of the flushing air ways, just beneath the hammer spline drive. This zone (patent pending) improves the evacuation by preventing accumulation of rocks and gravel at a recess point. By turning the driver against the fixed casing, the rock is crushed into smaller particles and then evacuated through the casing.
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.
Square Bit
The drill through bit is specially shaped to pass through the crown’s flats, and to drill the sub-casing hole to a maximum hole diameter, enabling in most of the cases, the use of a larger diameter hammer than the competition.