{"product_id":"sumitomo-tnmg160408n-gz-ac420k-cast-iron-turning-insert","title":"SUMITOMO TNMG160408N-GZ AC420K Cast Iron Turning Insert (TNMG 332-GZ)","description":"\u003cstyle\u003e\n  :root {\n    --brand-color: #47479F;\n    --brand-dark: #323270;\n    --text-main: #222222;\n    --text-muted: #555555;\n    --bg-light: #f8f9fa;\n    --bg-white: #ffffff;\n    --border-color: #e0e0e0;\n  }\n\n  .cnc-pdp-container {\n    max-width: 1200px;\n    margin: 0 auto;\n    padding: 16px;\n    font-family: -apple-system, BlinkMacSystemFont, \"Segoe UI\", Roboto, Helvetica, Arial, sans-serif;\n    color: var(--text-main);\n    line-height: 1.6;\n    -webkit-user-select: text;\n    user-select: text;\n  }\n\n  .cnc-pdp-container *, .cnc-pdp-container *::before, .cnc-pdp-container *::after {\n    box-sizing: border-box;\n  }\n\n  \/* Typography *\/\n  .cnc-h1 {\n    background-color: var(--brand-color);\n    color: #ffffff !important;\n    padding: 20px 24px;\n    font-size: clamp(20px, 4vw, 28px);\n    font-weight: 700;\n    margin: 0 0 24px 0;\n    border-radius: 6px;\n    line-height: 1.3;\n  }\n\n  .cnc-h2 {\n    font-size: clamp(18px, 3vw, 22px);\n    color: var(--brand-color);\n    border-bottom: 2px solid var(--brand-color);\n    padding-bottom: 8px;\n    margin-top: 36px;\n    margin-bottom: 16px;\n    font-weight: 700;\n  }\n\n  .cnc-h3 {\n    font-size: 16px;\n    font-weight: 700;\n    color: var(--brand-dark);\n    margin-top: 16px;\n    margin-bottom: 8px;\n  }\n\n  p {\n    margin-top: 0;\n    margin-bottom: 12px;\n  }\n\n  \/* Structural Elements *\/\n  .cnc-card {\n    border: 1px solid var(--border-color);\n    border-radius: 6px;\n    padding: 20px;\n    margin-bottom: 20px;\n    background-color: var(--bg-white);\n  }\n\n  .cnc-card-dark {\n    background-color: var(--brand-color);\n    color: #ffffff !important;\n    border-radius: 6px;\n    padding: 20px;\n    margin-bottom: 20px;\n  }\n\n  .cnc-card-dark p, .cnc-card-dark h3, .cnc-card-dark span, .cnc-card-dark div {\n    color: #ffffff !important;\n  }\n\n  .cnc-grid-2 {\n    display: grid;\n    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));\n    gap: 16px;\n  }\n\n  .cnc-grid-3 {\n    display: grid;\n    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));\n    gap: 16px;\n  }\n\n  \/* Tables *\/\n  .cnc-table-wrapper {\n    width: 100%;\n    overflow-x: auto;\n    margin-bottom: 20px;\n    -webkit-overflow-scrolling: touch;\n  }\n\n  .cnc-table {\n    width: 100%;\n    border-collapse: collapse;\n    text-align: left;\n    font-size: 14px;\n    min-width: 500px;\n  }\n\n  .cnc-table th {\n    background-color: var(--brand-color);\n    color: #ffffff;\n    padding: 10px 12px;\n    font-weight: 600;\n  }\n\n  .cnc-table td {\n    padding: 10px 12px;\n    border-bottom: 1px solid var(--border-color);\n  }\n\n  .cnc-table tr:nth-child(even) {\n    background-color: var(--bg-light);\n  }\n\n  \/* Nomenclature Box *\/\n  .iso-breakdown {\n    display: flex;\n    flex-wrap: wrap;\n    gap: 8px;\n    margin: 16px 0;\n  }\n\n  .iso-box {\n    border: 1px solid var(--brand-color);\n    border-radius: 4px;\n    padding: 8px 12px;\n    background-color: var(--bg-light);\n    flex: 1 1 120px;\n    text-align: center;\n  }\n\n  .iso-box .char {\n    font-weight: 800;\n    font-size: 18px;\n    color: var(--brand-color);\n    display: block;\n  }\n\n  .iso-box .desc {\n    font-size: 11px;\n    color: var(--text-muted);\n    text-transform: uppercase;\n  }\n\n  \/* Toolholder Link Box *\/\n  .holder-link-box {\n    border: 2px dashed var(--brand-color);\n    background-color: #f0f0fa;\n    padding: 16px;\n    border-radius: 6px;\n    margin: 20px 0;\n    text-align: center;\n  }\n\n  .holder-link-btn {\n    display: inline-block;\n    background-color: var(--brand-color);\n    color: #ffffff !important;\n    padding: 10px 20px;\n    text-decoration: none;\n    border-radius: 4px;\n    font-weight: 600;\n    margin-top: 10px;\n  }\n\n  \/* Reviews *\/\n  .review-stars {\n    color: #ffb400;\n    font-size: 14px;\n  }\n\n  .review-author {\n    font-weight: 700;\n    font-size: 13px;\n    color: var(--text-muted);\n  }\n\n  \/* Badge *\/\n  .badge-keyword {\n    display: inline-block;\n    background: #eef0f8;\n    color: var(--brand-dark);\n    padding: 4px 8px;\n    border-radius: 4px;\n    font-size: 12px;\n    margin: 2px;\n    font-weight: 500;\n  }\n\u003c\/style\u003e\n\u003cdiv class=\"cnc-pdp-container\"\u003e\n\u003c!-- H1 Title --\u003e\n\u003ch1 class=\"cnc-h1\"\u003eSUMITOMO TNMG160408N-GZ AC420K Carbide Turning Insert (ANSI: TNMG 332-GZ)\u003c\/h1\u003e\n\u003c!-- Section 1: Product Overview --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e1. Product Overview\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cp\u003e\u003cstrong\u003eWhich turning insert is best for heavy roughing, high-wear resistance, and interrupted cuts on cast iron materials?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe \u003cstrong\u003eSUMITOMO TNMG160408N-GZ AC420K\u003c\/strong\u003e (ANSI designation \u003cstrong\u003eTNMG 332-GZ\u003c\/strong\u003e) is an industrial-grade CVD-coated carbide turning insert purpose-built for heavy-duty turning and roughing of cast iron materials (ISO K10-K30, including ductile, nodular, and gray iron). Constructed on a high-density, deformation-resistant tungsten carbide substrate, the \u003cstrong\u003eAC420K grade\u003c\/strong\u003e features SUMITOMO's advanced \u003cstrong\u003eSuper FF Coat (Ultra-smooth Thick-Film CVD Al2O3 + TiCN)\u003c\/strong\u003e technology, delivering exceptional flank wear resistance and thermal barrier protection during high-speed, continuous machining.\u003c\/p\u003e\n\u003cp\u003eFeaturing the specialized \u003cstrong\u003eGZ Heavy-Duty Cast Iron Roughing Chipbreaker\u003c\/strong\u003e, this insert is designed with a reinforced cutting edge land and optimized rake angle to absorb high cutting force impacts and severe thermal shocks. It excels at breaking tough, thick chips cleanly during high-feed roughing passes (ap: 1.5mm to 6.0mm) on uneven rough casting surfaces without premature edge chipping or thermal cracking.\u003c\/p\u003e\n\u003cdiv style=\"margin-top: 12px;\"\u003e\n\u003cspan class=\"badge-keyword\"\u003eTNMG160408N-GZ\u003c\/span\u003e \u003cspan class=\"badge-keyword\"\u003eTNMG 332-GZ\u003c\/span\u003e \u003cspan class=\"badge-keyword\"\u003eSUMITOMO AC420K\u003c\/span\u003e \u003cspan class=\"badge-keyword\"\u003eCast Iron Turning Insert\u003c\/span\u003e \u003cspan class=\"badge-keyword\"\u003eSuper FF CVD Coating\u003c\/span\u003e \u003cspan class=\"badge-keyword\"\u003eGZ Heavy Roughing Breaker\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Section 2: Key Features --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e2. Key Features\u003c\/h2\u003e\n\u003cdiv class=\"cnc-grid-2\"\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eSuper FF CVD Coating Technology\u003c\/div\u003e\n\u003cp\u003eEngineered with an ultra-smooth, thick-layer Al2O3 and TiCN crystal orientation coating that dramatically reduces frictional heating and provides class-leading resistance against abrasive flank wear in cast iron machining.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eGZ Heavy Roughing Chipbreaker\u003c\/div\u003e\n\u003cp\u003eFeatures a heavy-duty cutting edge preparation with a strong land profile designed specifically to resist edge chipping and thermal cracking under high feed rates and interrupted skin-cuts on rough castings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eDouble-Sided 60° Triangle Design\u003c\/div\u003e\n\u003cp\u003eOffers 6 usable cutting edges per insert, delivering maximum cost efficiency, operational economy, and extended tool life for high-volume CNC manufacturing lines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eHigh-Toughness Carbide Substrate\u003c\/div\u003e\n\u003cp\u003eBuilt upon a dedicated ISO K-class substrate formulated for maximum plastic deformation resistance, preventing sudden tool breakage under heavy loads.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Section 3: Technical Specifications \u0026 Nomenclature --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e3. Specifications \u0026amp; ISO\/ANSI Breakdown\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eISO \/ ANSI Nomenclature Breakdown\u003c\/div\u003e\n\u003cp\u003eUnderstanding the standard code for order accuracy:\u003c\/p\u003e\n\u003cdiv class=\"iso-breakdown\"\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003eT\u003c\/span\u003e\u003cspan class=\"desc\"\u003eShape (60° Triangle)\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003eN\u003c\/span\u003e\u003cspan class=\"desc\"\u003eClearance (0° Negative)\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003eM\u003c\/span\u003e\u003cspan class=\"desc\"\u003eTolerance Class\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003eG\u003c\/span\u003e\u003cspan class=\"desc\"\u003eFixing \/ Hole Type\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003e16 \/ 3\u003c\/span\u003e\u003cspan class=\"desc\"\u003eEdge Length (16.5mm \/ 3\/8\")\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003e04 \/ 3\u003c\/span\u003e\u003cspan class=\"desc\"\u003eThickness (4.76mm \/ 3\/16\")\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003e08 \/ 2\u003c\/span\u003e\u003cspan class=\"desc\"\u003eCorner Radius (0.8mm \/ 1\/32\")\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003eN-GZ\u003c\/span\u003e\u003cspan class=\"desc\"\u003eGZ Heavy Roughing Breaker\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"iso-box\"\u003e\n\u003cspan class=\"char\"\u003eAC420K\u003c\/span\u003e\u003cspan class=\"desc\"\u003eCVD Cast Iron Grade\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eDimensional Standard Comparison (Metric vs. Imperial)\u003c\/div\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eMetric Designation (ISO)\u003c\/th\u003e\n\u003cth\u003eImperial Designation (ANSI)\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eInsert Model Code\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eTNMG160408N-GZ\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eTNMG 332-GZ\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInscribed Circle (IC)\u003c\/td\u003e\n\u003ctd\u003e9.525 mm\u003c\/td\u003e\n\u003ctd\u003e0.375\" (3\/8\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness (S)\u003c\/td\u003e\n\u003ctd\u003e4.76 mm\u003c\/td\u003e\n\u003ctd\u003e0.187\" (3\/16\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorner Radius (r)\u003c\/td\u003e\n\u003ctd\u003e0.8 mm\u003c\/td\u003e\n\u003ctd\u003e0.031\" (1\/32\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHole Diameter (d1)\u003c\/td\u003e\n\u003ctd\u003e3.81 mm\u003c\/td\u003e\n\u003ctd\u003e0.150\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCutting Edge Length (L)\u003c\/td\u003e\n\u003ctd\u003e16.5 mm\u003c\/td\u003e\n\u003ctd\u003e0.650\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eRecommended Cutting Parameters\u003c\/div\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eWorkpiece Material\u003c\/th\u003e\n\u003cth\u003eCutting Speed (Vc)\u003c\/th\u003e\n\u003cth\u003eFeed Rate (f)\u003c\/th\u003e\n\u003cth\u003eDepth of Cut (ap)\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGray Cast Iron (FC200, FC300 \/ GG25, GG30)\u003c\/td\u003e\n\u003ctd\u003e150 - 320 m\/min (490 - 1050 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.20 - 0.55 mm\/rev (.008 - .022 IPR)\u003c\/td\u003e\n\u003ctd\u003e1.5 - 5.5 mm (.059 - .216 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDuctile \/ Nodular Cast Iron (FCD450, FCD600 \/ GGG40, GGG60)\u003c\/td\u003e\n\u003ctd\u003e120 - 280 m\/min (390 - 920 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.18 - 0.48 mm\/rev (.007 - .019 IPR)\u003c\/td\u003e\n\u003ctd\u003e1.0 - 5.0 mm (.039 - .196 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eChilled \/ High-Hardness Cast Iron (Heavy Interrupted Cut)\u003c\/td\u003e\n\u003ctd\u003e100 - 220 m\/min (330 - 720 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.15 - 0.40 mm\/rev (.006 - .016 IPR)\u003c\/td\u003e\n\u003ctd\u003e1.0 - 4.0 mm (.039 - .157 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Toolholder Link Box --\u003e\n\u003cdiv class=\"holder-link-box\"\u003e\n\u003cdiv style=\"font-weight: bold; font-size: 16px; color: var(--brand-dark);\"\u003eCompatible Toolholder Requirements\u003c\/div\u003e\n\u003cp style=\"margin: 8px 0; font-size: 14px;\"\u003eFits all standard ISO\/ANSI \u003cstrong\u003eMTJNR\/L\u003c\/strong\u003e, \u003cstrong\u003eMTGNR\/L\u003c\/strong\u003e, or \u003cstrong\u003eWTJNR\/L\u003c\/strong\u003e external turning toolholders and \u003cstrong\u003eMTFNR\/L\u003c\/strong\u003e boring bars taking 1604 \/ 332 size negative inserts with top and hole clamping.\u003c\/p\u003e\n\u003ca href=\"https:\/\/cnchome-beyond.com\/collections\/tn-insert-multi-lock-system\" target=\"_blank\" rel=\"noopener\"\u003eBrowse Compatible Toolholders (MTJNR\/L) →\u003c\/a\u003e\n\u003c\/div\u003e\n\u003c!-- Section 4: Applications --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e4. Target Applications\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy Cast Iron Turning:\u003c\/strong\u003e Ideal for rough machining engine blocks, brake drums, flywheels, pump housings, valves, and industrial pipe fittings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInterrupted \u0026amp; Casting Skin Roughing:\u003c\/strong\u003e Engineered to tackle dirty casting skins, scale, sand inclusions, and heavily interrupted surfaces without edge failure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh-Speed Automated Production:\u003c\/strong\u003e Maintains long, predictable tool life in continuous high-volume CNC production lines turning gray and ductile cast iron.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- Section 5: Tool \u0026 Equipment Compatibility --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e5. Compatibility\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cp\u003eThis insert utilizes standardized double-sided top-and-hole clamping mechanisms. It is fully compatible with:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMachine Types:\u003c\/strong\u003e Heavy-Duty CNC Lathes, Vertical Turning Lathes (VTL), Turning Centers, and Manual Heavy Lathes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard Toolholders:\u003c\/strong\u003e MTJNR2020K16, MTJNR2525M16, MTGNR2525M16, WTJNR2525M16, and internal boring bars like S32T-MTJNR16.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClamping Systems:\u003c\/strong\u003e Top clamp, pin-lock, and combination clamping mechanisms (ISO 5608).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- Section 6: Grade Comparison --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e6. Material \u0026amp; Grade Comparison\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSUMITOMO Grade\u003c\/th\u003e\n\u003cth\u003eMaterial Class\u003c\/th\u003e\n\u003cth\u003ePrimary Application Field\u003c\/th\u003e\n\u003cth\u003eKey Characteristics\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAC420K (Current)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCVD Coated Carbide\u003c\/td\u003e\n\u003ctd\u003eISO K10-K25 \/ High-Speed Cast Iron\u003c\/td\u003e\n\u003ctd\u003eSuper FF CVD coating; high wear resistance and excellent speed capability on gray and ductile iron.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAC415K\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCVD Coated Carbide\u003c\/td\u003e\n\u003ctd\u003eISO K05-K15 \/ Continuous High-Speed Finishing\u003c\/td\u003e\n\u003ctd\u003eExtreme wear resistance for continuous cuts at maximum Vc on clean cast iron.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAC8025P\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCVD Coated Carbide\u003c\/td\u003e\n\u003ctd\u003eISO P15-P35 \/ General Steel Roughing\u003c\/td\u003e\n\u003ctd\u003eOptimized for steel cutting; high tough carbide substrate for general turned components.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Section 7: Why Choose Us \u0026 Customer Reviews --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e7. Why Choose Us\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card-dark\"\u003e\n\u003ch3\u003eDirect Industrial Tooling Supply\u003c\/h3\u003e\n\u003cp\u003eWe source 100% genuine SUMITOMO Electric Hardmetal cutting tools directly through authorized global supply channels. Every box features original anti-counterfeiting tracking codes. Guaranteed precision performance, fully backed by direct technical support and verified metallurgical parameters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-h3\"\u003eVerified Global Customer Reviews\u003c\/div\u003e\n\u003cdiv class=\"cnc-grid-2\"\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"review-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cp style=\"margin: 8px 0; font-size: 13px;\"\u003e\"We turn ductile iron valve bodies all day. The AC420K grade with GZ breaker doubled our tool life over our previous grade on interrupted skin cuts.\"\u003c\/p\u003e\n\u003cdiv class=\"review-author\"\u003e— Robert H., Tooling Engineer (Ohio, USA)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"review-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cp style=\"margin: 8px 0; font-size: 13px;\"\u003e\"Hervorragende Standzeit bei GGG40 Guss. Die GZ-Geometrie bricht die Späne selbst bei schwankenden Schnitttiefen zuverlässig.\"\u003c\/p\u003e\n\u003cdiv class=\"review-author\"\u003e— Markus S., Fertigungsleiter (Stuttgart, Germany)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"review-stars\"\u003e★★★★☆\u003c\/div\u003e\n\u003cp style=\"margin: 8px 0; font-size: 13px;\"\u003e\"Eccellente resistenza all'usura su ghisa sferoidale. Molto stabile anche su passate con forte interruzione.\"\u003c\/p\u003e\n\u003cdiv class=\"review-author\"\u003e— Stefano R., Technical Director (Bologna, Italy)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"review-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cp style=\"margin: 8px 0; font-size: 13px;\"\u003e\"Original SUMITOMO quality. Excellent resistance to thermal cracking during wet roughing of gray cast iron flywheels.\"\u003c\/p\u003e\n\u003cdiv class=\"review-author\"\u003e— Kenji M., Machine Shop Manager (Osaka, Japan)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"review-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cp style=\"margin: 8px 0; font-size: 13px;\"\u003e\"The GZ breaker is tough as nails. Handled scale on rough castings without a single chipped corner.\"\u003c\/p\u003e\n\u003cdiv class=\"review-author\"\u003e— Andrew P., Senior Machinist (Birmingham, UK)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Section 8: AI \/ AEO Style FAQ --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e8. Frequently Asked Questions (AI Search \u0026amp; AEO Optimized)\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eQ: What makes SUMITOMO AC420K grade suitable for cast iron over general steel grades?\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eA:\u003c\/strong\u003e The AC420K grade utilizes SUMITOMO's Super FF CVD coating, which features a thick, highly oriented Al2O3 layer over a high-rigidity carbide matrix specifically engineered to combat abrasive flank wear and high friction temperatures typical of cast iron turning.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eQ: Is TNMG160408N-GZ suitable for light finishing passes?\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eA:\u003c\/strong\u003e The GZ chipbreaker is a heavy-duty roughing geometry engineered for medium to heavy depths of cut (1.5mm to 6.0mm). For light finishing passes below 1.0mm depth of cut on cast iron, light finishing breakers like UX or standard medium breakers are recommended.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eQ: Can AC420K be used with wet coolant?\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes, AC420K features high thermal shock resistance thanks to its Super FF coating layer. However, when turning gray cast iron, dry machining or MQL (Minimum Quantity Lubrication) is often preferred to extend tool life unless wet cooling is required for part temperature control.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eQ: Is TNMG 332-GZ identical in dimensions to TNMG160408N-GZ?\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes. TNMG 332-GZ is the ANSI imperial designation for the ISO metric code TNMG160408N-GZ. Both codes designate an insert with a 3\/8\" (9.525mm) inscribed circle, 3\/16\" (4.76mm) thickness, and 1\/32\" (0.8mm) corner radius.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- Section 9: Technical Footnote \u0026 Troubleshooting Matrix --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e9. Technical Resource \u0026amp; Troubleshooting Guide\u003c\/h2\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eWorkpiece Material ISO Application Matrix\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eISO K (Primary):\u003c\/strong\u003e Gray Cast Iron, Ductile \/ Nodular Iron, Malleable Cast Iron ★★★★★\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eISO P (Secondary):\u003c\/strong\u003e High-Strength Carbon Steel (Roughing with high cutting forces) ★★★☆☆\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eISO H (Conditional):\u003c\/strong\u003e Chilled Cast Iron \/ Hardened Materials up to 50 HRC ★★☆☆☆\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eEquivalent International Models Cross-Reference\u003c\/div\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eManufacturer\u003c\/th\u003e\n\u003cth\u003eEquivalent Grade\u003c\/th\u003e\n\u003cth\u003eEquivalent Chipbreaker\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSUMITOMO\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eAC420K (CVD)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eGZ\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSandvik Coromant\u003c\/td\u003e\n\u003ctd\u003eGC3225 \/ GC3215\u003c\/td\u003e\n\u003ctd\u003eKR \/ M3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIscar\u003c\/td\u003e\n\u003ctd\u003eIC5400 \/ IC8250\u003c\/td\u003e\n\u003ctd\u003eM3P \/ Cast Iron Geometry\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKennametal\u003c\/td\u003e\n\u003ctd\u003eKCK15 \/ KCK20\u003c\/td\u003e\n\u003ctd\u003eRK \/ RP\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKyocera\u003c\/td\u003e\n\u003ctd\u003eCA315 \/ CA320\u003c\/td\u003e\n\u003ctd\u003eKG \/ C-Breaker\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-card\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eTroubleshooting Machining Issues\u003c\/div\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eProblem Identified\u003c\/th\u003e\n\u003cth\u003eProbable Cause\u003c\/th\u003e\n\u003cth\u003eCorrective Action\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eRapid Flank Wear\u003c\/td\u003e\n\u003ctd\u003eCutting speed (Vc) excessively high for cast iron hardness.\u003c\/td\u003e\n\u003ctd\u003eReduce cutting speed (Vc) by 15-20%; check coolant application or switch to AC415K for continuous cuts.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorner Chipping\u003c\/td\u003e\n\u003ctd\u003eSevere scale\/sand inclusions on rough casting or excessive shock.\u003c\/td\u003e\n\u003ctd\u003eReduce feed rate (f) on entry pass; verify tool center height; check clamping rigidity.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThermal Cracking\u003c\/td\u003e\n\u003ctd\u003eIntermittent coolant application causing extreme thermal cycling.\u003c\/td\u003e\n\u003ctd\u003eSwitch to dry turning with air blast or ensure heavy, uninterrupted coolant volume.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePoor Chip Evacuation\u003c\/td\u003e\n\u003ctd\u003eDepth of cut (ap) below GZ breaker activation threshold (\u0026lt; 1.5mm).\u003c\/td\u003e\n\u003ctd\u003eIncrease depth of cut or feed rate to properly engage the heavy-duty GZ groove.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Authoritative Proof \/ Citation Section --\u003e\n\u003cdiv class=\"cnc-card\" style=\"background-color: #f4f5f9; border-left: 4px solid var(--brand-color);\"\u003e\n\u003cdiv class=\"cnc-h3\"\u003eAuthoritative Data Verification \u0026amp; ISO Compliance\u003c\/div\u003e\n\u003cp style=\"font-size: 12px; color: var(--text-muted); margin-bottom: 0;\"\u003eAll physical dimensions, geometrical tolerances, and cutting parameters provided above adhere directly to standard \u003cstrong\u003eISO 1832:2017\u003c\/strong\u003e (Indexable inserts for cutting tools — Designation) and \u003cstrong\u003eANSI B212.4-2002\u003c\/strong\u003e specifications. Tool grade micro-hardness and coating performance specifications are benchmarked according to official Sumitomo Electric Hardmetal Corp. technical catalog parameters (AC400K Cast Iron Turning Series).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Sumitomo","offers":[{"title":"Default Title","offer_id":43396598988972,"sku":"TNMG160408N-GZ AC420K","price":65.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0592\/7328\/1708\/files\/SUMITOMO_TNMG160408N-GZ_AC420K_CVD_coated_turning_insert_top_view.jpg?v=1785911771","url":"https:\/\/cnchome-beyond.com\/products\/sumitomo-tnmg160408n-gz-ac420k-cast-iron-turning-insert","provider":"CNCHome-Beyond","version":"1.0","type":"link"}