What Are CNMG Inserts?

CNMG inserts are square-shaped, double-sided, negative-rake carbide inserts commonly used in CNC turning operations. Their geometry makes them especially well-suited for roughing and semi-finishing of hard materials like steel, stainless steel, and cast iron.

The CNMG code is derived from ISO naming conventions:

• C – 80° diamond (square) shape

• N – 0° relief angle (neutral rake)

• M – Medium tolerance

• G – Clamping and chipbreaker type

With 4 cutting edges per side (8 total), CNMG inserts offer excellent tool life, strong cutting edges, and high material removal rates.

Key Features of CNMG Inserts

• Geometry: Square-shaped insert with 80° cutting angle

• Rake Angle: Negative, 0° relief for high edge strength

• Edges: 8 usable cutting edges (4 on each side)

• Application Range: Medium to heavy-duty turning

• Versatility: Ideal for both roughing and interrupted cuts

• Compatibility: Fits most standard clamp-style toolholders

Applications

• Rough turning of alloy steel, mild steel, cast iron, and hardened materials

• Interrupted cuts due to high edge strength

• High-feed turning and stable cutting on heavy-duty CNC lathes

• Used in both external and internal turning tools

Material Grades and Coatings

CNMG inserts are available in various grades, including:

• Carbide – Most common, with high heat and wear resistance

• Cermet – For high-finish applications

• CBN – For hard turning

• Coatings:

  • CVD (TiCN/Al₂O₃/TiN) – High-speed machining

  • PVD (TiAlN, AlTiN) – Tougher applications, sharp edge retention

  • Uncoated – For low-speed, high-precision turning

Why Choose CNMG Inserts from CNC Tools Depot?

• Industrial-grade CNMG inserts from leading global brands

• Bulk order discounts and fast delivery

• Expert guidance for chipbreaker selection and insert grades

• Ideal for steel plants, auto parts machining, and general CNC operations