Rotary drilling deck bushings
Sandvik deck bushings centralize the drill pipe over the hole, prevent misaligment of the bit and drill string, thereby extending tools life. There are two types of deck bushings; static and rotating.
Static type bushings are utilized in DTH applications with low drilling string speed. Rotating bushings have an inner guide sleeve that is bearing mounted which allows for the inner guide sleeve to rotate with the drill string at higher penetration rate, resulting in less vibration, torque and drill pipe diamter gouging.