Sumitomo-Original Inserts from Japan

All 18 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 DN 55° Diamond Negative Inserts

Sumitomo 55° diamond negative inserts with hole provide better clearance than 80° (CN) for profiling and contour turning work. The 55° point balances edge strength with profile capability — making DN the preferred choice for finishing profiles on tough materials.

The DN-55-DIAMOND family includes sub-designations:

• DNMG — 55° Diamond Negative w/ Hole + Molded Chipbreaker

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 DN-55-DIAMOND Insert

Selecting the correct Sumitomo DN-55-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 → DNMG. Finishing → DNMG. 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.