CNMG 120408-MF3 OS9201S Carbide Turning Insert

The CNMG 120408-MF3 OS9201S is a negative-rake carbide turning insert designed for medium finishing operations on CNC and conventional lathes. Its 80° rhombic geometry ensures rigidity and secure positioning, while the 0.8 mm corner radius provides strength and stable cutting under moderate feed rates. This makes it suitable for semi-finishing cuts where both accuracy and surface quality are important.

The insert is produced in the OS9201S grade, which offers excellent wear resistance and heat resistance. Combined with the MF3 chipbreaker, it delivers smooth chip flow, reduced cutting forces, and a fine surface finish under continuous and stable cutting conditions. This makes it especially effective for machining stainless steels, titanium alloys, and high-temperature alloys.

The CNMG 120408-MF3 OS9201S fits common external turning tool holders, including MCLNR, PCLNR, and DCLNR, ensuring secure clamping and broad usability. It is widely applied in industries such as aerospace, automotive, and general engineering, where consistency and reliability in finishing operations are required.

Code Breakdown:

• C – Insert shape: 80° rhombic

• N – Clearance angle: 0° (negative rake)

• M – Tolerance class (medium)

• G – Insert with hole and chipbreaker

• 12 – Insert size: 12 mm

• 04 – Insert thickness: 4.76 mm

• 08 – Corner radius: 0.8 mm

• MF3 – Chipbreaker for medium finishing

• OS9201S – Grade optimized for stainless steel, titanium, and high-temp alloys

Key Features:

• CNMG-style 80° rhombic turning insert

• Size: 12×12 mm, thickness 4.76 mm, radius 0.8 mm

• Grade OS9201S – high wear resistance and thermal stability

• MF3 chipbreaker for smooth chip control and finishing quality

• Negative rake for stability and tool strength

• Fits holders: MCLNR, PCLNR, DCLNR

• Ideal for finishing stainless steels, titanium, and high-temp alloys

Grade Information (OS9201S):

• Coating: PVD, silver color

• Application: semi-finishing of titanium alloys, high-temp alloys, stainless steels (304, 316)

• Best for: continuous cutting in stable conditions

• Material hardness: HRC <45

• Cutting speed: 40–220 m/min