Patent ID: 6554550
Filing Date: 2003-04-29
Classification: B23G,Y10T

Abstract:
A tandem tap for cutting internal threads on an inner wall of a bore, the tap comprising:an elongate body for rotation about an axis, the elongate body extending between a workable end and a tip end, the elongate body including a first cutting section toward the tip end and a second cutting section between the first cutting section and the workable end, the workable end adapted to be worked for rotating the tandem tap, the first and second cutting sections including external threading of different thread characteristics wherein the first and second cutting sections are adapted to cuts threads having different characteristics; at least one first flute interrupting the external threading on the first cutting section, the first flute extending axially to the tip end, wherein when the first cutting section is cutting threads forming a plurality of chips, the chips are moved in a forward direction; and at least one spiral flute interrupting the external threading on the second cutting section, the spiral flute following a helical path leading toward the workable end, wherein when the second cutting section is cutting threads forming a plurality of chips, the chips are moved in a rearward direction opposite said forward direction.