Abstract: A well bore reamer has an elongated body for coupling between members of a well string, a first set of cutting elements on the body at a fixed position, a second set of cutting elements on a sleeve closing around a sleeve carrying portion of the elongated body. The sleeve is slidable along a longitudinal axis of the body and rotatable thereabout. A lower clutch mechanism operates between the sleeve and the elongated body at a bottom end of the body's sleeve carrying portion to block rotation of the sleeve relative to the elongated body in a predetermined direction about the longitudinal axis under sliding of the sleeve into a lowered position adjacent said bottom end of the sleeve carrying portion.

Abstract: A well bore reamer has an elongated body for coupling between members of a well string, a first set of cutting elements on the body at a fixed position, a second set of cutting elements on a sleeve closing around a sleeve carrying portion of the elongated body. The sleeve is slidable along a longitudinal axis of the body and rotatable thereabout. A lower clutch mechanism operates between the sleeve and the elongated body at a bottom end of the body's sleeve carrying portion to block rotation of the sleeve relative to the elongated body in a predetermined direction about the longitudinal axis under sliding of the sleeve into a lowered position adjacent said bottom end of the sleeve carrying portion.