CCMT vs CNMG: choosing a turning insert
Diamond Cut · Turning guide
CCMT or CNMG?
Start with the insert seat in your holder. These two 80° insert families look similar, but their clearance angles and holder requirements differ.
01Compare the insert families
| Feature | CCMT | CNMG |
|---|---|---|
| Kuju | 80° diamond | 80° diamond |
| Clearance angle | 7° | 0° |
| Typical selection priority | Lighter cutting and lower cutting forces | Edge security in a stable setup |
| Holder | Matching positive insert seat | Matching negative insert seat |
02Will it fit your holder?
CCMT and CNMG are not interchangeable simply because both have an 80° shape. Match the complete insert designation, size, thickness and fixing system to the holder specification. Also check the tool hand, approach angle and clearance for your operation.
Replacing an existing insert? Copy its full marking, including the size and corner radius. If the marking is unreadable, send a photo of the holder marking and insert seat.
03Choose the grade after the geometry
The family code describes the insert, not which material the carbide grade can machine. Check the ISO material group, chipbreaker, continuous or interrupted cutting suitability and the recommended cutting range on the individual product page.
Compare real products: CCMT 09T304-HMP OS8225 and CNMG 120404-TM OS8225. These examples have different sizes; choose the version specified for your holder.
04Technical references
Geometry references: Ingersoll CCMT designation and 7° clearance; Sandvik CNMG geometry and 0° clearance. These references explain standard geometry; their proprietary grades and cutting data are not recommendations for Diamond Cut grades.