Turning inserts are named by a standard code, and the first letter is the shape. Shape sets the balance between edge strength and access: rounder, larger-angle inserts are stronger, while pointed ones reach into tight contours but chip more easily.
| Code | Shape | Angle | Notes |
|---|---|---|---|
| C | Rhombic 80° | 80° | Strong and versatile; turning and facing |
| D | Rhombic 55° | 55° | Profiling and contour access |
| T | Triangle | 60° | Three edges, general purpose |
| R | Round | — | Strongest edge; finishing and copying |
| S | Square | 90° | Four edges, strong, facing |
| V | Rhombic 35° | 35° | Deep profiling; weakest tip |
| W | Trigon | 80° | Three strong edges |
Reading the full code: shape, clearance angle, tolerance, and type, followed by size, thickness, and nose radius — for example CNMG 432.
Choose the largest, strongest shape that still reaches the feature. See the Tool Coating Comparison for grade selection.