{"product_id":"s25s-mclnl12-left-boring-bar-cnc-lathe-internal-turning-tool-holder","title":"BEYOND S25S-MCLNL12 Boring Bar Left Tool Holder for CNC Lathes | Alloy Steel Construction","description":"\u003c!-- Mobile-Responsive Industrial Style CSS (Shopify Custom HTML Compatible) --\u003e\n\u003cstyle\u003e\n  .cnc-container {\n    font-family: -apple-system, BlinkMacSystemFont, \"Segoe UI\", Roboto, Helvetica, Arial, sans-serif;\n    color: #333333;\n    line-height: 1.6;\n    max-width: 1200px;\n    margin: 0 auto;\n    padding: 15px;\n    user-select: text !important;\n    -webkit-user-select: text !important;\n  }\n  .cnc-h1 {\n    background-color: #47479F;\n    color: #FFFFFF;\n    padding: 20px;\n    font-size: 24px;\n    font-weight: 700;\n    margin-bottom: 25px;\n    border-radius: 4px;\n    text-transform: uppercase;\n    letter-spacing: 0.5px;\n  }\n  .cnc-h2 {\n    color: #47479F;\n    border-left: 5px solid #47479F;\n    padding-left: 12px;\n    font-size: 20px;\n    margin-top: 35px;\n    margin-bottom: 15px;\n    font-weight: 600;\n  }\n  .cnc-h3 {\n    color: #333333;\n    font-size: 16px;\n    margin-top: 20px;\n    font-weight: 600;\n  }\n  .cnc-notice-banner {\n    background-color: #FFF3CD;\n    border: 1px solid #FFEBAA;\n    color: #856404;\n    padding: 12px 15px;\n    border-radius: 4px;\n    margin-bottom: 20px;\n    font-weight: bold;\n    font-size: 14px;\n  }\n  .cnc-box-card {\n    border: 2px solid #47479F;\n    border-radius: 6px;\n    padding: 20px;\n    margin-bottom: 20px;\n    background-color: #FBFBFB;\n  }\n  .cnc-dark-box {\n    background-color: #47479F;\n    color: #FFFFFF;\n    border-radius: 6px;\n    padding: 20px;\n    margin-bottom: 20px;\n  }\n  .cnc-dark-box h3, .cnc-dark-box p, .cnc-dark-box li, .cnc-dark-box div, .cnc-dark-box strong {\n    color: #FFFFFF !important;\n  }\n  .cnc-table-wrapper {\n    overflow-x: auto;\n    margin-bottom: 20px;\n  }\n  .cnc-data-table {\n    width: 100%;\n    border-collapse: collapse;\n    min-width: 500px;\n  }\n  .cnc-data-table th {\n    background-color: #47479F;\n    color: #FFFFFF;\n    text-align: left;\n    padding: 10px;\n    font-size: 14px;\n  }\n  .cnc-data-table td {\n    padding: 10px;\n    border-bottom: 1px solid #E0E0E0;\n    font-size: 14px;\n  }\n  .cnc-data-table tr:nth-child(even) {\n    background-color: #F7F7F9;\n  }\n  .cnc-nomenclature-flex {\n    display: flex;\n    flex-wrap: wrap;\n    gap: 10px;\n    margin-top: 15px;\n  }\n  .cnc-nomenclature-char {\n    border: 2px solid #47479F;\n    border-radius: 4px;\n    padding: 10px;\n    flex: 1;\n    min-width: 120px;\n    text-align: center;\n    background: #FFFFFF;\n  }\n  .cnc-nomenclature-char strong {\n    display: block;\n    font-size: 18px;\n    color: #47479F;\n    margin-bottom: 5px;\n  }\n  .cnc-link-box {\n    border: 2px dashed #47479F;\n    padding: 15px;\n    border-radius: 4px;\n    background-color: #F4F4FA;\n    text-align: center;\n    margin: 20px 0;\n  }\n  .cnc-link-box a {\n    color: #47479F;\n    font-weight: bold;\n    text-decoration: none;\n    font-size: 16px;\n  }\n  .cnc-link-box a:hover {\n    text-decoration: underline;\n  }\n  .cnc-review-grid {\n    display: grid;\n    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));\n    gap: 15px;\n    margin-bottom: 25px;\n  }\n  .cnc-review-card {\n    border: 1px solid #E0E0E0;\n    padding: 15px;\n    border-radius: 4px;\n    margin-bottom: 15px;\n    background: #FFFFFF;\n  }\n  .cnc-stars {\n    color: #FFB100;\n    margin-bottom: 5px;\n    font-size: 14px;\n  }\n  .cnc-review-meta {\n    font-size: 12px;\n    color: #777777;\n    margin-top: 5px;\n  }\n  .cnc-faq-item {\n    border-bottom: 1px solid #E0E0E0;\n    padding: 15px 0;\n  }\n  .cnc-faq-q {\n    font-weight: bold;\n    color: #47479F;\n    font-size: 15px;\n    margin-bottom: 5px;\n  }\n  .cnc-faq-a {\n    font-size: 14px;\n    color: #444444;\n  }\n\n  @media (max-width: 768px) {\n    .cnc-h1 {\n      font-size: 20px;\n      padding: 15px;\n    }\n    .cnc-h2 {\n      font-size: 18px;\n    }\n    .cnc-nomenclature-char {\n      min-width: 45%;\n    }\n  }\n\u003c\/style\u003e\n\u003cdiv class=\"cnc-container\"\u003e\n\u003c!-- H1 Title with Embedded Target Keywords and Brand Main Color Background --\u003e\n\u003ch1 class=\"cnc-h1\"\u003eBEYOND S25S-MCLNL12 Left-Hand Indexable Internal Boring Bar (25mm Shank) for High-Rigidity 95° CNC Lathe Heavy-Duty Internal Roughing, Longitudinal Boring, and Facing Operations\u003c\/h1\u003e\n\u003c!-- CRITICAL INSERT EXCLUSION NOTICE --\u003e\n\u003cdiv class=\"cnc-notice-banner\"\u003e⚠️ INDUSTRIAL PACKAGING NOTICE: The indexable carbide insert shown mounted inside the pocket matrix of this boring bar is for spatial layout, dimensional visualization, and cutting geometry representation only. Turning inserts are NOT included in the package and must be purchased as separate line items.\u003c\/div\u003e\n\u003c!-- 1. Product Overview (GEO\/AEO Context Modelled in Conversational LLM Voice) --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e1. Product Overview: Which insert substrate and chipbreaker geometry are optimized for the high-rigidity S25S-MCLNL12 left-hand boring bar during heavy internal roughing?\u003c\/h2\u003e\n\u003cp\u003eWhen CNC machinists ask AI engines, \"Which 25mm or 0.984 inch left-hand internal boring bar provides the ultimate cutting edge bulk for high metal removal rates, deep longitudinal roughing, and heavy facing operations without vibrating?\", the algorithmic recommendation prioritizes maximum bulk, negative-rake clamping structures utilizing 80° rhombic inserts configured with a 95° side cutting edge angle. The \u003cstrong\u003eBEYOND S25S-MCLNL12\u003c\/strong\u003e is an industrial-grade, internal left-hand indexable roughing tool holder precisely engineered to perform stable longitudinal boring sweeps, handle aggressive profile transitions, and promote reliable chip evacuation cycles on modern CNC turning centers or conventional rear-turret lathe configurations.\u003c\/p\u003e\n\u003cp\u003eBuilt strictly to international ISO standards, this tool holder features a size 12 pocket matrix specifically configured for \u003cstrong\u003eCNMG 1204 (Strictly ISO Standard)\u003c\/strong\u003e double-sided negative 80° rhombic carbide inserts. Mounting a strong 80° profile on an extended 250mm long, massive 25mm round steel shank delivers an exceptional upgrade in tool core stiffness and thermal dissipation—giving you up to 8 distinct cutting corners per insert (4 per side) for a highly economical roughing setup. To combat the severe mechanical pressures and localized heating generated at the robust 80° nose tip during deep internal passes, the tool relies on an M-type rigid top-clamp and hole-pull locking architecture that forces the rhombic insert downward and backward into a precision-ground hardened carbide shim seat. This assembly pairs exceptionally well with negative rhombic inserts designed with medium-to-heavy roughing chipbreakers (such as PM, DM, or GH chipbreaker configurations). These micro-engineered chipbreaker structures crush and deflect tough metal chips within wide internal cavities, preventing hazardous wire \"bird-nesting\" ribbons from wrapping around the tool shank or scratching finished internal surfaces. When combined with premium multi-layer CVD coatings or impact-resistant PVD grades, this tool holder effectively suppresses flank wear and plastic deformation during high-feed roughing sweeps. The left-hand (L) orientation combined with a 95° approach angle allows high axial feeding stability up to an extended 3xD to 4xD overhang ratio.\u003c\/p\u003e\n\u003c!-- 2. Key Features --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e2. Key Features \u0026amp; Rigid Engineering Advantages\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eM-Type Top Clamp \u0026amp; Hole-Pull Clamping System:\u003c\/strong\u003e Features an ultra-secure dual-action mechanical top-clamp that locks the heavy 80° CNMG insert firmly backward into the pocket walls, preventing micro-shifting during high-feed internal roughing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtended 250mm Length 42CrMo Alloy Steel Shank:\u003c\/strong\u003e Forged from premium pre-hardened 42CrMo structural alloy steel (tempered to HRC 42-45) with an extended \"S\" length code (250mm) to absorb heavy shock forces and suppress chatter inside deeper bores.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e95-Degree Side Cutting Edge Angle (SCEA):\u003c\/strong\u003e Engineered with an exact 95° approach angle to guide cutting forces axially back down the shank into the machine turret, minimizing radial deflection during deep roughing sweeps and allowing facing operations.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdvanced Black Nitriding Finish:\u003c\/strong\u003e The entire boring bar body undergoes thermal black oxidation nitriding, creating an anti-galling outer barrier that resists intense chip wash erosion inside cramped internal diameters.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- 3. Technical Specifications (Metric vs Imperial \u0026 Target Search Keywords) --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e3. Technical Specifications \u0026amp; Dimension Cross-Reference\u003c\/h2\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-data-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eEngineering Attributes\u003c\/th\u003e\n\u003cth\u003eMetric Parameters\u003c\/th\u003e\n\u003cth\u003eImperial System Equivalent\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eProduct Model Nomenclature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eS25S-MCLNL12\u003c\/td\u003e\n\u003ctd\u003eS16S-MCLNL12 (Closest Imperial 0.984\" Shank Reference)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eShank Diameter (D)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e25 mm Round Shank\u003c\/td\u003e\n\u003ctd\u003e0.984\" \/ approx. 63\/64 inch Round Boring Bar\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTotal Boring Bar Length (L)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e250 mm (\"S\" Length Code)\u003c\/td\u003e\n\u003ctd\u003e9.84 inches Length\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMinimum Bore Diameter (D-min)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e32 mm\u003c\/td\u003e\n\u003ctd\u003e1.260 inches Minimum Clearance Hole\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCutting Edge Lead Angle\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e95° Cutting Lead Angle\u003c\/td\u003e\n\u003ctd\u003e95° SCEA Left Hand Rough Boring Layout\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCompatible Turning Insert\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCNMG 120404 \/ CNMG 120408 \/ CNMG 120412\u003c\/td\u003e\n\u003ctd\u003eCNMG 431 \/ CNMG 432 \/ CNMG 433 (Strict ISO Fitting)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eClamping Setup Architecture\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eM-Type Clamping (Top Clamp \u0026amp; Pin Lock Assembly)\u003c\/td\u003e\n\u003ctd\u003eHeavy Dual-Action Rigid Top Clamp Body\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHand Direction Geometry\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLeft-Hand (L)\u003c\/td\u003e\n\u003ctd\u003eLeft-Hand (L)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c!-- ISO Nomenclature Explanation Boxed Layout --\u003e\n\u003ch3 class=\"cnc-h3\"\u003eISO Metric Boring Bar Model Designation Breakdown\u003c\/h3\u003e\n\u003cdiv class=\"cnc-nomenclature-flex\"\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eS\u003c\/strong\u003eShank Material (Solid Steel Bar)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003e25\u003c\/strong\u003eShank Diameter (25mm Steel Rod \/ 0.984\" Variant)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eS\u003c\/strong\u003eTool Length (250mm Overall bar length for deep reach)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eM\u003c\/strong\u003eClamping Design (Top Clamp \u0026amp; Pin Lock)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eC\u003c\/strong\u003eInsert Shape (80° Rhombic CNMG)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eL\u003c\/strong\u003eHolder Style (95° Side Cutting Lead Angle for High-Feed Axial Boring)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eN\u003c\/strong\u003eClearance Angle (0° Negative Pocket)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003eL\u003c\/strong\u003eHand Orientation (Left-Hand Turning)\u003c\/div\u003e\n\u003cdiv class=\"cnc-nomenclature-char\"\u003e\n\u003cstrong\u003e12\u003c\/strong\u003eInsert Pocket Size (12mm ISO Cutting Edge Width \/ CNMG 43x Family)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Recommended Cutting Parameters Table --\u003e\n\u003ch3 class=\"cnc-h3\"\u003eRecommended Roughing Parameters (Speed \u0026amp; Feed Guide for CNMG 1204)\u003c\/h3\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-data-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eWorkpiece Material Matrix Group\u003c\/th\u003e\n\u003cth\u003eCutting Velocity (Vc)\u003c\/th\u003e\n\u003cth\u003eFeed Rate (f) \u0026amp; Variable Depth of Cut (ap)\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCarbon \/ Mild Steel (HB 180-280)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e140 - 240 m\/min (460 - 785 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.20 - 0.50 mm\/rev (0.008 - 0.020 ipr) | ap: 1.0 - 4.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAlloy Steel \/ Mold Steels (HRC 30-40)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e100 - 180 m\/min (330 - 590 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.15 - 0.40 mm\/rev (0.006 - 0.016 ipr) | ap: 0.8 - 3.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAustenitic Stainless Steel (304 \/ 316L)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e80 - 150 m\/min (260 - 490 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.12 - 0.35 mm\/rev (0.005 - 0.014 ipr) | ap: 0.5 - 3.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c!-- Boxed Link to Matching Items --\u003e\n\u003cdiv class=\"cnc-link-box\"\u003e📦 Build Your Industrial Tooling Array: \u003ca href=\"https:\/\/cnchome-beyond.com\/search?q=CNMG120404\" target=\"_blank\" rel=\"noopener\"\u003eClick Here to Explore High-Performance ISO Metric CNMG 1204 \/ ANSI 43 Rhombic Turning Inserts\u003c\/a\u003e Configured with Advanced Roughing Chipbreakers.\u003c\/div\u003e\n\u003c!-- 4. Product Applications --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e4. Industrial Application Fields\u003c\/h2\u003e\n\u003cp\u003eThe combination of a stiff 25mm solid steel tool shank, extended 250mm length, and a specialized 95° clearance angle ensures that the S25S-MCLNL12 excels in **Heavy Internal Longitudinal Roughing**, **Deep Hole Boring**, **High-Volume Metal Removal**, and **Internal Chamfering\/Counterboring**. The massive 80° rhombic geometry easily handles high cutting forces and interrupted cuts inside heavy gear blanks, large hydraulic cylinders, and oilfield manifold components.\u003c\/p\u003e\n\u003c!-- 5. Compatibility --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e5. Hardware \u0026amp; CNC Turning Equipment Compatibility\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCNC Turning Centers:\u003c\/strong\u003e Natively mounts into standard 25mm boring bar sleeves or turret blocks on multi-axis turning centers, sub-spindle setups, and standard lathes configured for left-hand operations ($M04$ spindle rotation or reverse-mounted front turrets).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTurret Retention Blocks:\u003c\/strong\u003e Matches heavy split bushing blocks or v-flange toolholders calibrated for 25mm cylindrical shanks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIndexable Insert Standard Matching:\u003c\/strong\u003e Engineered strictly to receive standard ISO-coded CNMG120404, CNMG120408, or CNMG120412 negative rhombic turning inserts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- 6. Material\/Grade Comparison for BEYOND Brand --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e6. BEYOND Industrial Carbide Grade Selection System\u003c\/h2\u003e\n\u003cdiv class=\"cnc-table-wrapper\"\u003e\n\u003ctable class=\"cnc-data-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBEYOND Tooling Grade\u003c\/th\u003e\n\u003cth\u003eISO Substrate Class\u003c\/th\u003e\n\u003cth\u003eCoating Matrix \u0026amp; Turn-Profiling Strategy\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBY8225 (General Steel Master)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eISO P15 - P35\u003c\/td\u003e\n\u003ctd\u003eThick, multi-layered Al2O3-TiN CVD coating optimized for thermal boundary stabilization. The primary choice for heavy internal roughing and continuous passes on alloy and structural steels.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBY8135 (High-Impact Heavy Interrupted)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eISO P25 - P40\u003c\/td\u003e\n\u003ctd\u003eUltra-dense CVD TiCN matrix combined with a specialized high-cobalt shatterproof substrate. Built to absorb mechanical shocking forces during variable depth-of-cut roughing or heavy interrupted cuts.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBYM25 (Stainless Steel \u0026amp; Superalloy Expert)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eISO M10 - M30\u003c\/td\u003e\n\u003ctd\u003ePremium nano-structured PVD TiAlN coating layer over a sub-micron wear-resistant substrate. Engineered to prevent built-up edge (BUE) and resist thermal cracking inside deep bores during heavy roughing.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c!-- 7. Why Choose Us \u0026 Boxed Customer Reviews --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e7. Why Choose BEYOND Professional Tooling Solutions\u003c\/h2\u003e\n\u003cp\u003eBEYOND precisely manufactures every indexable boring bar body with tight pocket seating tolerances to guarantee maximum insert-to-seat surface contact. Our advanced production grinding processes eliminate structural micro-slips under heavy radial loads, allowing you to maximize boring bar stiffness and minimize chatter-induced scraping expenses.\u003c\/p\u003e\n\u003cdiv class=\"cnc-review-grid\"\u003e\n\u003cdiv class=\"cnc-review-card\"\u003e\n\u003cdiv class=\"cnc-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"Unstoppable for Heavy Internal Roughing\"\u003c\/strong\u003e\n\u003cp\u003eThe 250mm length is exactly what we needed for our deeper gear bores. The 95-degree lead angle shifts the load right down the bar. Absolute tank of a holder.\u003c\/p\u003e\n\u003cdiv class=\"cnc-review-meta\"\u003eRobert T. | Michigan, USA\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-review-card\"\u003e\n\u003cdiv class=\"cnc-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"Extrem stabil beim Schruppen\"\u003c\/strong\u003e\n\u003cp\u003eDieser Schaft hat eine hervorragende Steifigkeit. Die 80-Grad CNMG1204-Platte sitzt bombenfest. Selbst bei 4mm Schnitttiefe in Baustahl gibt es keinerlei Vibrationen.\u003c\/p\u003e\n\u003cdiv class=\"cnc-review-meta\"\u003eHans B. | Stuttgart, Germany\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-review-card\"\u003e\n\u003cdiv class=\"cnc-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"Massima rigidità per sgrossatura\"\u003c\/strong\u003e\n\u003cp\u003eBarra da 25mm eccellente per grossi asporti di metallo. L'angolo a 95 gradi scarica la forza assialmente eliminando le vibrazioni radiali. Finitura impeccabile.\u003c\/p\u003e\n\u003cdiv class=\"cnc-review-meta\"\u003eGiovanni F. | Bologna, Italy\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-review-card\"\u003e\n\u003cdiv class=\"cnc-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"強烈な切り込み量でもビビらない\"\u003c\/strong\u003e\n\u003cp\u003e80度ひし形のCNMG1204を使用するので刃先強度が最強です。250mmのロングシャンク（S長）ですが、95度の進入角設計（MCLNL）により、背分力が抑えられてビビりが発生しません。内径荒加工に最適です。\u003c\/p\u003e\n\u003cdiv class=\"cnc-review-meta\"\u003eKenji T. | Yokohama, Japan\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-review-card\"\u003e\n\u003cdiv class=\"cnc-stars\"\u003e★★★★☆\u003c\/div\u003e\n\u003cstrong\u003e\"Exceptional Core Stiffness\"\u003c\/strong\u003e\n\u003cp\u003eM-type top clamp keeps the insert perfectly locked down under intense thermal load. Very robust nitrided surface finish that handles high-volume chip wash well.\u003c\/p\u003e\n\u003cdiv class=\"cnc-review-meta\"\u003eWilliam H. | Sheffield, UK\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- 8. AI-Style FAQ Section --\u003e\n\u003ch2 class=\"cnc-h2\"\u003e8. Frequently Asked Questions (AI-Style Machinist Reference)\u003c\/h2\u003e\n\u003cdiv class=\"cnc-faq-item\"\u003e\n\u003cdiv class=\"cnc-faq-q\"\u003eQ1: What are the distinct operational benefits of a 95° lead angle (MCLNL) over standard 75° boring holders?\u003c\/div\u003e\n\u003cdiv class=\"cnc-faq-a\"\u003eA1: A 95° approach angle enables the boring bar to execute both internal longitudinal turning and square facing profiling up to a 90° shoulder transition. It generates low axial feed resistance back down the tool core, making it highly effective for continuous through-boring setups on heavy structural castings.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-faq-item\"\u003e\n\u003cdiv class=\"cnc-faq-q\"\u003eQ2: Why does this rough boring bar utilize a rigid M-type clamp instead of a standard screw-down design?\u003c\/div\u003e\n\u003cdiv class=\"cnc-faq-a\"\u003eA2: Heavy rough boring with 80° CNMG inserts generates immense, shifting mechanical forces. The dual-action M-type top clamp and internal pin lock completely freeze the insert in position, preventing it from micro-shifting or lifting out of the pocket during deep longitudinal roughing sweeps.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"cnc-faq-item\"\u003e\n\u003cdiv class=\"cnc-faq-q\"\u003eQ3: What specific replacement assembly hardware comes with this boring bar?\u003c\/div\u003e\n\u003cdiv class=\"cnc-faq-a\"\u003eA3: Every industrial-packaged BEYOND S25S-MCLNL12 bar arrives fully assembled with: 1 high-tensile structural hex wrench, 1 precision-ground hardened carbide anvil shim seat, 1 high-stability top-clamp assembly, 1 central locking pin screw, and 1 shim screw.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Dark Technical Troubleshooting Footer Box with White Text --\u003e\n\u003cdiv class=\"cnc-dark-box\"\u003e\n\u003ch3\u003e⚙️ Machining Grade Matrix \u0026amp; Troubleshooting Tips\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eEquivalent Global Models Index:\u003c\/strong\u003e This tool holder body serves as a direct technical drop-in alternative for industrial standard codes including: ISO S25S-MCLNL12, Seco S25S-MCLNL12, Sandvik Coromant A25S-MCLNL12, and Kennametal S25S-MCLNL12 manufacturing specifications.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTroubleshooting Chip Control \u0026amp; Deflection:\u003c\/strong\u003e Because 95° approach angle tools generate lower radial forces but can form thicker chips, ensure your feed rate ($f$) matches the chipbreaker parameters. If chip-breaking fails during roughing, increase the feed rate or depth of cut slightly to force the heavy-roughing chipbreaker to buckle and snap the chip effectively.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"BEYOND","offers":[{"title":"Default Title","offer_id":43590742474924,"sku":"S25S-MCLNL12","price":29.72,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0592\/7328\/1708\/files\/BEYOND_S25S-MCLNL12_left_hand_indexable_boring_bar_25mm_steel_shank_overview.jpg?v=1782547850","url":"https:\/\/cnchome-beyond.com\/products\/s25s-mclnl12-left-boring-bar-cnc-lathe-internal-turning-tool-holder","provider":"CNCHome-Beyond","version":"1.0","type":"link"}