Patent ID: 7112143

Claim:
Cold thread forming tap or screw tap comprising a shaft having two ends, said shaft having a chuck portion at the one end and a forming or cutting profile portion on the other end, the forming or cutting profile portion being realised as a separate profile element and being fixable centrically and secured against rotation on the shaft by means of a fixing device, the profile portion having a small axial length and an outside, the outside having lead-in or starting tap cone, juts and/or indentations formed on the profile portion facing the shaft, which interlock in a positively fitting manner, that an automatic centering of the profile portion takes place on the shaft when the profile portion is put onto the shaft, the juts and indentations comprising complementary lateral areas, inclined with respect to an axis of the shaft and the profile portion, respectively, which are in gearing for the purpose of centering and transmission of torque, wherein the profile portion does not have more than two to four complete thread forming convolutions.