Carbide insert designation decoder
Type a turning or milling insert code and read what each position means under ISO 1832. Nothing is sent anywhere; the code is decoded in your browser.
CNMG120408 is a 80° rhombic turning insert.
| C | Shape | 80° rhombic |
|---|---|---|
| N | Clearance angle | 0° (negative insert) |
| M | Tolerance class | Class M |
| G | Hole and chipbreaker | Cylindrical hole, chipbreaker on both faces |
| 12 | Cutting edge length code | About 12 mm |
| 04 | Thickness | 4.76 mm |
| 08 | Corner | 0.8 mm nominal |
ISO insert designation chart
A metric ISO designation has four letters and a size code. The tables below list the values this tool reads. Dimensions are nominal values from the standard.
1st letter: shape
| A | 85° parallelogram |
| B | 82° parallelogram |
| C | 80° rhombic |
| D | 55° rhombic |
| E | 75° rhombic |
| H | Hexagonal |
| K | 55° parallelogram |
| L | Rectangular |
| M | 86° rhombic |
| O | Octagonal |
| P | Pentagonal |
| R | Round |
| S | Square |
| T | 60° triangular |
| V | 35° rhombic |
| W | 80° trigon |
2nd letter: clearance angle
| A | 3° |
| B | 5° |
| C | 7° |
| D | 15° |
| E | 20° |
| F | 25° |
| G | 30° |
| N | 0° (negative insert) |
| P | 11° |
3rd letter: tolerance class
The third letter (A, C, E, F, G, H, J, K, L, M, N or U) sets the tolerances on the inscribed circle, the corner height and the thickness. M and G are common classes: M is typical of pressed inserts and G of inserts ground on the periphery.
4th letter: hole and chipbreaker
| A | Cylindrical hole, no chipbreaker |
| B | Hole countersunk on one side, no chipbreaker |
| C | Hole countersunk on both sides, no chipbreaker |
| F | No hole, chipbreaker on both faces |
| G | Cylindrical hole, chipbreaker on both faces |
| H | Hole countersunk on one side, chipbreaker on one face |
| J | Hole countersunk on both sides, chipbreaker on both faces |
| M | Cylindrical hole, chipbreaker on one face |
| N | No hole, no chipbreaker |
| Q | Hole countersunk on both sides, no chipbreaker |
| R | No hole, chipbreaker on one face |
| T | Hole countersunk on one side, chipbreaker on one face |
| U | Hole countersunk on both sides, chipbreaker on both faces |
| W | Hole countersunk on one side, no chipbreaker |
Thickness code
| 12 | 12.7 mm |
| 01 | 1.59 mm |
| T1 | 1.98 mm |
| 02 | 2.38 mm |
| T2 | 2.78 mm |
| 03 | 3.18 mm |
| T3 | 3.97 mm |
| 04 | 4.76 mm |
| 05 | 5.56 mm |
| 06 | 6.35 mm |
| 07 | 7.94 mm |
| 09 | 9.52 mm |
Corner code
| 00 | Sharp corner; on round inserts, an inch-based diameter |
| 02 | 0.2 mm |
| 04 | 0.4 mm |
| 08 | 0.8 mm |
| 12 | 1.2 mm |
| 16 | 1.6 mm |
| 20 | 2.0 mm |
| 24 | 2.4 mm |
| 32 | 3.2 mm |
| M0 | Round insert, metric diameter |
Milling inserts often carry letters in place of the corner radius, for example PDER in APMT1604PDER. They describe the wiper edge angles, the edge preparation and the cutting direction.
Questions
- What does CNMG120408 mean?
- C is an 80° rhombic shape, N a 0° clearance angle (a negative insert), M the tolerance class and G a cylindrical hole with a chipbreaker on both faces. 12 is the cutting edge length code, 04 a thickness of 4.76 mm and 08 a corner radius of 0.8 mm.
- Are the letters after the dash part of the ISO code?
- No. A suffix such as the letters after CNMG120408- is the maker's own chipbreaker or grade code. Two makers can use different suffixes for similar geometries, so compare the geometry, not only the letters.
- Is the first size number the edge length in millimetres?
- It is the cutting edge length rounded down to a whole number of millimetres. For round inserts it is the diameter. Holders and cutters name the insert sizes they take, but confirm the fit with the pocket and clamping system.
- Why do some inserts have T3 in the code?
- T3 is a thickness code: 3.97 mm, between 03 (3.18 mm) and 04 (4.76 mm). It appears in sizes such as CCMT09T304 and DCMT11T304.
See the 409 ISO sizes we make →
Guides: CNMG vs WNMG vs DNMG vs TNMG · ISO material groups P, M, K, N, S, H · Inserts for stainless steel