Turning Inserts
How to Read ISO Insert Codes
Decode ISO insert codes so you can order the right insert shape, tolerance, thickness, and nose radius.
5/8/2026•By CAGO technical team
ISO CNMG Inserts CNC
ISO insert codes describe shape, clearance angle, tolerance, clamping style, size, thickness, and nose radius.
Example: CNMG 120408
C is an 80-degree diamond shape, N is 0-degree clearance, M is medium tolerance, and G defines the hole and chipbreaker style.
Understanding the code reduces ordering mistakes and helps machinists choose inserts faster.