| 摘要 |
Provided is a thread-cutting tap, which limits chipping that occurs during tapping and with which female thread precision is also stabilized. Chipping is limited by forming a protruding circular shape (32) on the cutting face (30) of a cutting edge (28). Moreover, the thrust load (Fs), which acts on the negative side when the spiral tap (10) bites into the material that is being cut, is reduced and excessive advancement of the spiral tap (10) is also eliminated. Consequently, because spiral tap (10) cutting conditions are favorable, female thread precision is also stabilized. |
