滾刀可以看作是一個具有漸伸線螺紋的平行蝸桿,經過開槽和鏟齒(Relieved)後,使具有切削刃口。假使將這蝸桿和一齒輪毛胚相接觸,並給以一定吃刀深度;則當二者按一定關係旋轉,並使滾刀有一沿齒輪毛胚軸心向下進刀的運動時,於是 The hob can be thought of as a parallel worm with involute thread, having a cutting edge after being slotted and Relieved. If the worm and a gear blank embryo in contact with, and to give a certain depth of eating knife; then when the two under a certain relationship between the rotation, and the hob has a gear along the axis of the knife down into the knife movement, then