US Patent 7293617 Polycrystaline diamond compact insert reaming tool

A reaming tool including a body adapted to couple to a drill string at both axial ends thereof, the body including a plurality of reaming blades affixed at azimuthally spaced apart locations around the circumference of the body, wherein selected ones of the plurality of reaming blades including at least one cutter attached at a selected position and orientation. Additionally, a pilot hole conditioning section including a plurality of azimuthally spaced apart pilot blades affixed to the body longitudinally ahead of the reaming blades. Furthermore, at least one of the reaming blades formed as a single structure with an azimuthally corresponding pilot blade.