The present invention provides a burr in the form of a generally cylindrical rod, the burr having a proximal end for mounting in a tool for rotating the burr and a distal cutting end, the burr having a cutting portion defined by a portion of a surface of the burr which comprises a plurality of teeth, the cutting portion including and extending from the distal end back towards the proximal end, wherein the cutting portion comprises a cylindrical portion of a first diameter and a distal end portion of a second diameter that is greater than the first diameter. The burr is particularly suited to the drilling of cylinder locks.

A cutting tool and method of manufacturing a tool including determining desired flowrates to cutting edges. The method includes calculating pressure drop and passage dimensions for each of an nth-number of passages to the cutting edges based on I.sub.n=(P.sub.n*A.sub.n.sup.n)/(.sub.n*L.sub.n), wherein I.sub.n is nth-passage flow rate, P.sub.n is nth-passage pressure drop, A.sub.n.sup.n is nth-passage cross-sectional area raised to a power n, the power n being equal to 1 or 0.5, .sub.n is nth-passage resistivity, and L.sub.n is nth-passage length. The method includes forming the nth-passages in the tool open to each cutting edge based on the nth-passage dimensions.

A cutting tool and method of manufacturing a tool including determining desired flowrates to cutting edges. The method includes calculating pressure drop and passage dimensions for each of an nth-number of passages to the cutting edges based on I.sub.n=(P.sub.n*A.sub.n.sup.n)/(.sub.n*L.sub.n), wherein I.sub.n is nth-passage flow rate, P.sub.n is nth-passage pressure drop, A.sub.n.sup.n is nth-passage cross-sectional area raised to a power n, the power n being equal to 1 or 0.5, .sub.n is nth-passage resistivity, and L.sub.n is nth-passage length. The method includes forming the nth-passages in the tool open to each cutting edge based on the nth-passage dimensions.