Generally, it refers to the method of machining thread on workpiece with forming tool or grinding tool, mainly including turning, milling, tapping, threading, grinding and whirlwind cutting, etc.
When turning, milling and grinding the thread, the transmission chain of the machine tool ensures that the turning tool, milling cutter or grinding wheel moves a lead accurately and evenly along the axial direction of the workpiece every rotation of the workpiece. When tapping or threading, the tool (tap or die) rotates relative to the workpiece, and the first formed thread groove guides the tool (or workpiece) to move axially.
Thread turning on lathe can use forming turning tool or thread carding tool (see thread processing tool). Turning thread with forming turning tool is a common method for single piece and small batch production of thread workpieces due to its simple structure; turning thread with thread cutting tool has high production efficiency, but its structure is complex. So it is only suitable for turning short thread workpieces with fine teeth in medium and large batch production. The pitch accuracy of turning trapezoidal thread with general lathe can only reach 8-9 levels (jb2886-81, the same below); the productivity or accuracy can be significantly improved when machining thread on specialized thread lathe.