What Is Turning?
Turning a machining process where a machine — typically a lathe — removes material from a rotating workpiece with a cutting tool. With turning, the workpiece moves while the cutting tool remains stationary.
Boring is another machining process that involves the use of a lathe. With both boring and turning, the lathe’s stationary cutting tool presses against a rotating workpiece. The difference is that turning is designed to remove material from the exterior of a workpiece, whereas boring is designed to remove material from the interior of a workpiece. Boring, for instance, can be used to enlarge pre-drilled holes in a workpiece by removing material from the hole’s inner walls.
What Is Milling?
Milling, on the other hand, is a machining process where a machine — typically a milling machine — removes material from a stationary workpiece with a rotating cutting tool. The principle behind this machining process is similar to that of turning: a cutting tool presses against a workpiece, thereby removing material from it. The main difference between these two machining processes lies in their use of rotation. In turning operations, the workpiece rotates. In milling operations, the cutting tool rotates.
Turning Vs Milling Overview
| Turning | Milling | |
| Method | Rotates workpiece at pre-set RPM | Rotates cutting tool at pre-set RPM |
| Result | Cylindrical or conical | Flat or sculptured |
| Machine | Lathe | Milling machine |
| Tool | Single point turning tool (SPTT) | Multi-point cutting tool (milling cutter) |
| Contact | Cutting tool remains in continuous contact with workpiece during operation | Cutting tool cuts intermittently during operation |
| Movement (feed motion) | Cutting tool moves | Workpiece moves |
| Waste | Produces fragmented, discontinuous, or continuous chips | Produces discontinuous chips |