CCMT06 vs. 09 vs. 12: Does Insert Size Really Matter?
In the world of CNC turning, the CCMT insert is a staple. But a common question arises: "If a CCMT06 can cut steel, why would I need a CCMT12?"
Choosing the correct insert size isn't just about what fits your tool holder—it’s about rigidity, heat dissipation, and maximum depth of cut. Using a size that is too small for a large workpiece can lead to vibration and broken inserts, while using a size too large for small parts can limit your clearance. Here is how to choose based on your specific job.
1. CCMT06 (The Small Diameter Specialist)
The CCMT0602 series is designed for precision and light-duty work. Its thin profile (2.38mm) makes it ideal for internal boring where space is extremely limited.
- Best Workpiece Diameter: 5mm to 20mm.
- Max Depth of Cut (Ap): Recommended up to 1.5mm - 2.0mm.
- Best Use Case: Small internal boring bars, Swiss-type lathes, and delicate finishing on small shafts.
Shop Recommendation: Korloy CCMT060204 NC3120
2. CCMT09 (The Universal Workhorse)
The CCMT09T3 is the industry standard. It strikes a perfect balance between strength and versatility. Most general-purpose external turning holders use this size.
- Best Workpiece Diameter: 20mm to 50mm.
- Max Depth of Cut (Ap): Recommended up to 3.0mm - 3.5mm.
- Best Use Case: General-purpose external turning and medium-sized internal boring. It’s the "safe" choice for most workshops.
Shop Recommendation: Korloy CCMT09T304 NC3120
3. CCMT12 (The Heavyweight for Large Parts)
When you move to larger diameters and forged parts, you need the CCMT1204. Its increased thickness (4.76mm) provides massive heat resistance and mechanical strength.
- Best Workpiece Diameter: 50mm and above.
- Max Depth of Cut (Ap): Recommended up to 4.5mm - 5.0mm.
- Best Use Case: Heavy roughing, large diameter shafts, and high-feed operations where metal removal rate (MRR) is the priority.
Shop Recommendation: Korloy CCMT120408 NC3020
Quick Selection Table
| Insert Size | Thickness | Typical Boring Bar Dia. | Application |
|---|---|---|---|
| CCMT06 | 2.38 mm | ø8mm - ø12mm | Miniature / Internal |
| CCMT09 | 3.97 mm | ø16mm - ø20mm | General Purpose |
| CCMT12 | 4.76 mm | ø25mm + | Roughing / Large Shafts |
Important Factor: The "2/3 Rule"
A professional tip for choosing size: Your depth of cut (Ap) should not exceed 2/3 of the insert's cutting edge length. If you are forcing a CCMT06 to take a 4mm deep cut, you are risking a catastrophic tool failure. Switch to a CCMT12 for safety and better chip control.
Conclusion
Match your insert size to the scale of your workpiece. Small for precision, Medium for versatility, Large for power.
Ready to upgrade your shop's performance? Explore our full Korloy CCMT Collection here and find the perfect fit for your CNC machine.
