US Patent 8007050 Degradation assembly

A degradation assembly comprises a rotating portion and a fixed portion. The rotating portion comprises a wear resistant tip bonded to a carbide bolster. The bolster is attached to a shaft adapted for a rotatable connection within a bore of the fixed portion. The fixed portion is adapted for a rigid connection to a driving mechanism. The fixed portion includes an O-ring slot formed within its bore and with an O-ring being disposed therein. The O-ring is at least 15 percent compressed such that the O-ring resists rotation of the shaft.