Patent ID: 8418784

Claim:
A drilling assembly, comprising: a head located on a rotational axis of the assembly; at least one blade extending distally from the head; a plurality of blade degradation elements being rotationally supported on the blade; each degradation element comprising an attack angle formed between a central axis of the degradation element and the rotational axis of the assembly that affects the penetration rate of each degradation element and a laterally offset angle formed between the central axis of the degradation element and a line tangent to a helical cutting path of the degradation element that primarily affects the rotational rate of each degradation element within their holders fixed to the blade; wherein the plurality of blade degradation elements comprise a wear resistant tip comprising a pointed sintered polycrystalline diamond compact supported on a cemented metal carbide support; and a central cutting region of each blade; wherein the attack angle of each blade degradation element within the central cutting region is between 15 and 20 degrees.