CUTTING TAP AND METHOD OF MAKING A CUTTING TAP

摘要

A cutting tap that has an elongate tap body (22) with a fluted section (30) at the axial forward end (24) thereof wherein the fluted section (30) includes a chamfered fluted section (54) and a finishing fluted section (56). Each cutting thread (58, 62, 66, 68) in the chamfered fluted section (54) has a cutting face (72, 76, 80) disposed at a cutting face angle that becomes more negative the more axially rearward the cutting thread (58, 62, 66, 68) is from the axial forward end (24) of the chamfered fluted section (54). Each cutting thread (58, 62, 66, 68) in the finishing fluted section (56) has a cutting face (72, 76, 80) disposed at a finishing cutting face angle that is essentially equal. The finishing cutting face angle is more negative than the cutting face angle for the cutting thread at the axial rearward termination of the chamfered fluted section (54).