Product Description
The SECO 03273901 is a CNMG431-MF4 indexable turning insert in grade TM2501, designed for precision metal cutting on CNC lathes and turning centers. Built from solid carbide with a CVD-applied Duratomic multilayer coating of TiCN, Al2O3, and Cr, this insert delivers wear resistance and thermal stability in demanding applications. It features an 80-degree diamond shape, a 0.5-inch inscribed circle, a 0.0157-inch corner radius, and an MF4 chip breaker geometry optimized for light-to-medium finishing cuts. With four usable cutting edges and a negative rake angle, it offers extended tool life and consistent surface quality. Licensed HVAC and metalworking machinists and toolroom technicians will recognize the ANSI and ISO standard geometry immediately.
This insert is suited for turning, facing, and boring operations on stainless steel as its primary workpiece material, with steel as the secondary. It falls into ISO material grades M25, M30, and M35, making it well-matched for austenitic and duplex stainless alloys in both roughing and finishing passes at moderate depths of cut. The MF4 chip breaker geometry is engineered to produce manageable chips at lower feed rates typical of finishing work, reducing vibration and built-up edge. It is applicable to production turning, job shop work, and component repair environments where consistent insert performance across a batch is critical.
Key Features
- CVD Duratomic multilayer coating: TiCN, Al2O3, and Cr for heat and wear resistance
- MF4 chip breaker geometry optimized for finishing and light turning on stainless steel
- Four cutting edges per insert for extended tool economy
- Negative rake, chamfered and honed cutting edge for edge strength
- Compatible with clamp, pin, and lever lock insert holding methods
- Meets ANSI and ISO standards; ISO code CNMG120404-MF4
Compatibility
Designed as an OEM-style replacement or direct tooling insert for CNMG-style turning toolholders that accept CNMG431 geometry with clamp, pin, or lever lock holding methods per ANSI and ISO standards.
Installation Notes
Installation is performed by qualified machinists or toolroom technicians during setup of CNC or manual turning equipment. Always power down and lock out the machine before indexing or replacing inserts. Use the correct torque driver or clamp screw specified by the toolholder manufacturer do not over-tighten, as this can fracture the carbide insert. Inspect the insert seat and shim for wear or debris before seating the new insert to ensure proper contact and cutting geometry.
Technical Specifications
- Insert Style: CNMG
- Industry Standard Number: CNMG431-MF4
- ISO Code: CNMG120404-MF4
- Manufacturer Grade: TM2501
- Insert Material: Carbide
- Coating: TiCN, Al2O3, Cr (CVD Duratomic)
- Insert Shape: Diamond 80 (Code C)
- Included Angle: 80 degrees
- Inscribed Circle: 0.5 inches
- Corner Radius: 0.0157 inches (1/64 inches)
- Insert Thickness: 0.1874 inches (3/16 inches)
- Insert Length: 0.5079 inches
- Hole Diameter: 0.2028 inches
- Maximum Depth of Cut: 0.4917 inches
- Number of Cutting Edges: 4
- Rake: Negative
- Rake Angle: 30 degrees
- Relief Angle: 0 degrees
- Clearance Code: N
- Tolerance Code: M
- Chip Breaker: MF4
- Cutting Edge Style: Chamfered and Honed
- Insert Hand: Neutral
- Insert Holding Method: Clamp, Pin, Lever Lock
- Primary Workpiece Material: Stainless Steel (Code M)
- Secondary Workpiece Material: Steel (Code P)
- Material Grade: M25, M30, M35
- Multi-Use Application: Boring, Facing, Turning
- Standards: ANSI, ISO
- Weight: 0.19 pounds
Standard Information
- Brand: SECO
- Manufacturer Part Number: 03273901








