Rotatable bit having a resilient retainer sleeve with clearance

摘要

A drilling bit for use in conjunction with a holder that has a bore wherein the drilling bit has a drilling bit body that has an axial forward end and an axial rearward end. The drilling bit body further includes a reduced diameter portion adjacent to the axial rearward end thereof so as to define a reduced diameter surface. A hard insert is affixed to the drilling bit body at the axial forward end thereof. A resilient retainer sleeve has a first thickness and presents an interior surface. The retainer sleeve is carried by the drilling bit body within the reduced diameter portion. The resilient retainer sleeve is in an expanded condition when the drilling bit is not within the bore of the holder and the resilient retainer sleeve is in a compressed condition when the drilling bit being within the bore of the holder. The clearance between the reduced diameter surface of the drilling bit body and the interior surface of the resilient retainer sleeve when the resilient retainer sleeve is in its compressed condition is at least as great as the thickness of the resilient retainer sleeve.