Sumitomo-Original Inserts from Japan

All 75 inserts in this catalog are 100% genuine Sumitomo — manufactured by Sumitomo Electric Industries in Itami, Japan. Each insert is sourced through Sumitomo's authorized distribution channels and ships in original Sumitomo factory packaging with full Sumitomo grade and lot traceability. Sumitomo's premium carbide substrates, CVD/PVD coatings, and edge-preparation processes are specified across the full AC / NC / GC / KW / A-series grade families — providing the consistent performance and reliability that has made Sumitomo a leading Japanese cutting-tool brand.

About CN 80° Diamond Negative Inserts

Sumitomo 80° diamond negative inserts with hole provide the heaviest-duty turning geometry for steel, stainless, and cast iron. The 80° point with negative rake delivers maximum edge strength — making CN the preferred choice for heavy roughing and interrupted cuts where positive geometry would fail.

The CN-80-DIAMOND family includes sub-designations:

• CNMG — 80° Diamond Negative w/ Hole + Molded Chipbreaker
• CNMM — 80° Diamond Negative w/ Hole + Molded Chipbreaker + Thicker

Sumitomo Electric Industries (Itami, Japan) is one of the world's leading manufacturers of CNC cutting tools, with over 100 years of carbide expertise. The Sumitomo AC series (CVD/PVD-coated steel), NC series (cermet + stainless), GC series (aluminum + cast iron), and A-series (ceramic) represent decades of grade development.

How to Choose the Right Sumitomo CN-80-DIAMOND Insert

Selecting the correct Sumitomo CN-80-DIAMOND insert involves three decisions:

1. Material → Grade: Steel → AC6020M / AC6030M. Stainless → NC5330 / NC5340. Cast iron → NC40 series. Aluminum → GC3040 / KW10.
2. Sub-designation → Operation: General turning → CNMG. Finishing → CNMG. Heavy roughing → thicker section.
3. IC size → Tool holder: Smaller IC fits compact holders. Larger IC for heavy-duty work.

Tip: For stainless steel work, Sumitomo NC5330 / NC5340 (CVD M-grade) provide superior wear resistance. For aluminum, use uncoated GC3040 or KW10 with sharp-edge geometry.