{"product_id":"sumitomo-16gc258-pcbn-turning-insert-3-8-in-ic-diamond","title":"Sumitomo 16GC258 Pcbn Turning Insert 3\/8 in Ic Diamond","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe SUMITOMO 16GC258 is a polycrystalline cubic boron nitride (PCBN) turning insert designed for machining hard materials on CNC lathes and turning centers. Manufactured to ANSI code NUVNMA331 and ISO code NU-VNMA160404, this insert features a 35-degree diamond shape, a 3\/8 inch (0.3750 inch) inscribed circle, and a negative rake geometry with a clearance code of N and tolerance code of M. The BN350 grade is uncoated PCBN, suited for interrupted or continuous cuts on hardened steels, cast irons, and similar hard workpiece materials. Machinists and tool crib professionals handling precision turning applications will recognize the VNMA-style geometry immediately.\u003c\/p\u003e\u003cp\u003eThis insert is applied in hard turning operations where conventional carbide tooling reaches its limits. It is suited for finishing passes on hardened steels and hard ferrous materials in both production and job-shop environments. The 35-degree diamond shape and 1\/64 inch (0.0156 inch) corner radius make it appropriate for contour turning and light finishing cuts. The insert is held by clamp and pin methods, consistent with standard VNMA-style toolholders used across CNC turning applications in automotive, aerospace, and general precision machining.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003ePCBN insert material (BN350 grade) for hard material turning\u003c\/li\u003e\n\u003cli\u003e35-degree diamond insert shape with negative rake geometry\u003c\/li\u003e\n\u003cli\u003e3\/8 inch inscribed circle, 3\/16 inch insert thickness\u003c\/li\u003e\n\u003cli\u003e1\/64 inch corner radius for finish turning and light contouring\u003c\/li\u003e\n\u003cli\u003eUncoated for direct PCBN performance without coating interference\u003c\/li\u003e\n\u003cli\u003eCompatible with clamp and pin holding methods (VNMA-style toolholders)\u003c\/li\u003e\n\u003cli\u003eMeets ANSI and ISO 13399 standards\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as an OEM-style replacement insert conforming to ANSI code NUVNMA331 and ISO code NU-VNMA160404, fitting standard VNMA-style insert toolholders that accept a 35-degree diamond insert with clamp and pin retention.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation is performed by qualified machinists or toolroom personnel. Power down and lock out the machine spindle before seating or indexing the insert. Use the appropriate torx or hex key to secure the clamping screw to the toolholder manufacturer's specified procedure. Inspect the insert pocket and seating surfaces for chips or debris before mounting to ensure proper insert contact and runout.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eInsert Material\u003c\/strong\u003e: Polycrystalline Cubic Boron Nitride (PCBN)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Grade\u003c\/strong\u003e: BN350\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eANSI Code\u003c\/strong\u003e: NUVNMA331\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eISO Code\u003c\/strong\u003e: NU-VNMA160404\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInsert Shape\u003c\/strong\u003e: Diamond (35-degree included angle)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInsert Style\u003c\/strong\u003e: NU-VNMA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInscribed Circle\u003c\/strong\u003e: 3\/8 inch (0.3750 inch)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInsert Thickness\u003c\/strong\u003e: 3\/16 inch (0.1875 inch)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorner Radius\u003c\/strong\u003e: 1\/64 inch (0.0156 inch)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInsert Length\u003c\/strong\u003e: 0.1102 inch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHole Diameter\u003c\/strong\u003e: 0.1500 inch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRake\u003c\/strong\u003e: Negative\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRelief Angle\u003c\/strong\u003e: 0 degrees\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClearance Code\u003c\/strong\u003e: N\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTolerance Code\u003c\/strong\u003e: M\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChip Breaker\u003c\/strong\u003e: A\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoating\u003c\/strong\u003e: Uncoated\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrimary Workpiece Material\u003c\/strong\u003e: Hard Material (Code H)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInsert Holding Method\u003c\/strong\u003e: Clamp and Pin\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial Grade\u003c\/strong\u003e: C2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandards\u003c\/strong\u003e: ANSI, ISO 13399\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.2 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: SUMITOMO\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 16GC258\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SUMITOMO","offers":[{"title":"Default Title","offer_id":51735299752242,"sku":"16GC258","price":60.76,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/d3dbfd9de43352f79b93d683ca6e6f91.jpg?v=1788771598","url":"https:\/\/voomisupply.com\/products\/sumitomo-16gc258-pcbn-turning-insert-3-8-in-ic-diamond","provider":"Voomi Supply","version":"1.0","type":"link"}