{"product_id":"beyond-s20r-stfpl11-boring-bar-holder-tpmt1103","title":"BEYOND S20R-STFPL11 Left Hand Internal Turning Tool Holder | 20mm CNC Boring Bar","description":"\u003cstyle\u003e\n  .beyond-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    box-sizing: border-box;\n  }\n  .beyond-h1-holder {\n    background-color: #47479F;\n    color: #ffffff;\n    padding: 20px;\n    border-radius: 6px;\n    margin-bottom: 25px;\n  }\n  .beyond-h1-holder h1 {\n    margin: 0;\n    font-size: 24px;\n    font-weight: 700;\n    text-transform: uppercase;\n    letter-spacing: 0.5px;\n    color: #ffffff;\n  }\n  .beyond-section {\n    margin-bottom: 35px;\n  }\n  .beyond-section h2 {\n    color: #47479F;\n    border-left: 5px solid #47479F;\n    padding-left: 12px;\n    font-size: 20px;\n    margin-bottom: 15px;\n    font-weight: 600;\n  }\n  .beyond-section h3 {\n    color: #333333;\n    font-size: 16px;\n    margin-top: 20px;\n    margin-bottom: 10px;\n    font-weight: 600;\n  }\n  .beyond-alert-box {\n    background-color: #fff3cd;\n    border: 1px solid #ffeeba;\n    color: #856404;\n    padding: 15px;\n    border-radius: 6px;\n    margin-bottom: 25px;\n    font-weight: bold;\n  }\n  .beyond-grid-box {\n    border: 2px solid #47479F;\n    border-radius: 6px;\n    padding: 20px;\n    margin-bottom: 25px;\n    background-color: #fcfcfd;\n  }\n  .beyond-code-breakdown {\n    display: flex;\n    flex-wrap: wrap;\n    gap: 10px;\n    margin-top: 15px;\n  }\n  .beyond-code-letter {\n    border: 1px solid #47479F;\n    border-radius: 4px;\n    padding: 10px;\n    flex: 1 1 140px;\n    background-color: #ffffff;\n    text-align: center;\n    box-sizing: border-box;\n  }\n  .beyond-code-letter strong {\n    color: #47479F;\n    font-size: 18px;\n    display: block;\n    border-bottom: 1px solid #e0e0e0;\n    padding-bottom: 5px;\n    margin-bottom: 5px;\n  }\n  .beyond-table-wrapper {\n    width: 100%;\n    overflow-x: auto;\n    margin: 15px 0;\n  }\n  .beyond-table {\n    width: 100%;\n    border-collapse: collapse;\n    min-width: 600px;\n  }\n  .beyond-table th, .beyond-table td {\n    border: 1px solid #dddddd;\n    padding: 12px;\n    text-align: left;\n    font-size: 14px;\n  }\n  .beyond-table th {\n    background-color: #47479F;\n    color: white;\n    font-weight: 600;\n  }\n  .beyond-table tr:nth-child(even) {\n    background-color: #f8f9fa;\n  }\n  .beyond-link-box {\n    border: 2px dashed #47479F;\n    background-color: #f4f4fa;\n    padding: 15px;\n    border-radius: 6px;\n    text-align: center;\n    margin: 20px 0;\n  }\n  .beyond-link-box a {\n    color: #47479F;\n    font-weight: bold;\n    text-decoration: underline;\n  }\n  .beyond-review-container {\n    display: block;\n  }\n  .beyond-review-card {\n    border: 1px solid #e0e0e0;\n    border-radius: 6px;\n    padding: 15px;\n    margin-bottom: 15px;\n    background-color: #ffffff;\n    box-shadow: 0 2px 4px rgba(0,0,0,0.02);\n  }\n  .beyond-stars {\n    color: #ffc107;\n    margin-bottom: 5px;\n    font-size: 14px;\n  }\n  .beyond-review-meta {\n    font-size: 12px;\n    color: #777777;\n    margin-top: 5px;\n  }\n  .beyond-faq-item {\n    background-color: #f8f9fa;\n    border-left: 4px solid #47479F;\n    padding: 15px;\n    margin-bottom: 12px;\n    border-radius: 0 6px 6px 0;\n  }\n  .beyond-faq-q {\n    font-weight: bold;\n    color: #47479F;\n    margin-bottom: 5px;\n  }\n  .beyond-badge-container {\n    display: flex;\n    flex-wrap: wrap;\n    gap: 10px;\n    margin-top: 15px;\n  }\n  .beyond-badge {\n    background-color: #47479F;\n    color: white;\n    padding: 6px 12px;\n    border-radius: 20px;\n    font-size: 13px;\n    font-weight: 500;\n  }\n  .beyond-footer-panel {\n    border-top: 1px solid #e0e0e0;\n    padding-top: 25px;\n    margin-top: 30px;\n  }\n  @media (max-width: 768px) {\n    .beyond-h1-holder h1 { font-size: 20px; }\n    .beyond-section h2 { font-size: 18px; }\n    .beyond-code-letter { flex: 1 1 45%; }\n  }\n\u003c\/style\u003e\n\u003cdiv class=\"beyond-container\"\u003e\n\u003c!-- H1 Product Header --\u003e\n\u003cdiv class=\"beyond-h1-holder\"\u003e\n\u003ch1\u003eBEYOND S20R-STFPL11 Left-Hand Internal Turning Tool Holder – High-Rigidity CNC Boring Bar\u003c\/h1\u003e\n\u003c\/div\u003e\n\u003c!-- IMPORTANT NOTICE BLOCK --\u003e\n\u003cdiv class=\"beyond-alert-box\"\u003e⚠️ PLEASE NOTE: The indexable carbide insert shown in the product images is for structural demonstration purposes only and is NOT included in the tool holder package. Please purchase your compatible inserts separately.\u003c\/div\u003e\n\u003c!-- 1. Product Overview --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e1. Product Overview\u003c\/h2\u003e\n\u003cp\u003e\u003cem\u003e\"Which 20mm left-hand boring bar provides the optimal chip clearance and rigidity for internal turning in blind holes down to 25mm?\"\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003eThe \u003cstrong\u003eBEYOND S20R-STFPL11\u003c\/strong\u003e is an industrial-grade, left-handed steel-shank internal turning tool holder precisely engineered for medium-diameter, high-accuracy lathe boring operations. This industrial tool holder utilizes an optimized 91-degree approach angle to balance radial and axial cutting forces, preventing axis deflection during deep internal profiling. Specifically engineered for \u003cstrong\u003eTPMT 1103\u003c\/strong\u003e indexable carbide inserts, it allows machinists to harness the full potential of positive rake chipbreaker geometries (such as HQ for high-feed finish turning or HM for general medium machining). This setup delivers superb chip fragmentation control, preventing long stringy nesting when processing sticky alloy steels, carbon steels, and stainless steel matrices inside deep, confined chambers.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- 2. Product Key Features --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e2. Product Core Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHardened Structural Alloy Steel:\u003c\/strong\u003e Fabricated from a heavy-duty, high-tensile alloy steel body, tempered to absorb harmonic frequencies and dramatically reduce chatter during deep internal boring cycles.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eErgonomic Screw-Down Clamping Matrix:\u003c\/strong\u003e The ultra-low-profile screw lock mechanism ensures maximum clearance space inside internal walls, avoiding standard chip accumulation errors and ensuring smooth evacuation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision Engineered 91° Lead Angle:\u003c\/strong\u003e Optimized for cutting up to slight steps, boring blind holes, and executing internal profiling adjustments without dragging the tool flank body.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIndustrial Anti-Corrosion Matte Finish:\u003c\/strong\u003e Enhanced surface treated layout delivers extended tool life and resists rust when continuously exposed to high-pressure water-soluble coolants.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- 3. Technical Specifications --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e3. Technical Specifications \u0026amp; Metric\/Imperial Reference\u003c\/h2\u003e\n\u003cp\u003eEnsuring clear parameter conversion is vital for CNC programming optimization. Below is the precise structural parsing of the \u003cstrong\u003eS20R-STFPL11\u003c\/strong\u003e standard international nomenclature rules:\u003c\/p\u003e\n\u003c!-- Model Code Breakdown Box --\u003e\n\u003cdiv class=\"beyond-grid-box\"\u003e\n\u003cdiv style=\"font-weight: bold; color: #47479f; margin-bottom: 10px;\"\u003eISO Nomenclature Verification Structure:\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-breakdown\"\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eS\u003c\/strong\u003eSteel Shank\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003e20\u003c\/strong\u003e20mm Shank Dia.\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eR\u003c\/strong\u003e200mm Length\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eS\u003c\/strong\u003eScrew Lock System\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eT\u003c\/strong\u003eTriangular Insert\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eF\u003c\/strong\u003e91° Approach\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eP\u003c\/strong\u003e11° Clearance\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003eL\u003c\/strong\u003eLeft-Hand Direction\u003c\/div\u003e\n\u003cdiv class=\"beyond-code-letter\"\u003e\n\u003cstrong\u003e11\u003c\/strong\u003e11mm Edge Length\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Metric vs Imperial \u0026 Models Comparison Table --\u003e\n\u003cdiv class=\"beyond-table-wrapper\"\u003e\n\u003ctable class=\"beyond-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter Dimension\u003c\/th\u003e\n\u003cth\u003eMetric System Specification\u003c\/th\u003e\n\u003cth\u003eImperial Equivalent Measurement\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eShank Diameter (d)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e20 mm\u003c\/td\u003e\n\u003ctd\u003e0.7874 inches (Approx. 25\/32\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTotal Tool Length (L)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e200 mm\u003c\/td\u003e\n\u003ctd\u003e7.8740 inches\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\u003e25 mm\u003c\/td\u003e\n\u003ctd\u003e0.9843 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCompatible Carbide Insert Layout\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eTPMT 1103 \/ TPGT 1103\u003c\/td\u003e\n\u003ctd\u003eTPMT 221 \/ TPMT 222\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eClamping Screw Model Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eM2.5 x 6.0\u003c\/td\u003e\n\u003ctd\u003eM2.5 x 0.24 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTorx Key Driver Wrench Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eT8\u003c\/td\u003e\n\u003ctd\u003eT8 Torx Wrench\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c!-- Recommended Cutting Parameters Table --\u003e\n\u003ch3\u003eRecommended Technical Machining Parameters (Speed \u0026amp; Feed Guide)\u003c\/h3\u003e\n\u003cdiv class=\"beyond-table-wrapper\"\u003e\n\u003ctable class=\"beyond-table\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eWorkpiece Material Classification\u003c\/th\u003e\n\u003cth\u003eCutting Speed (Vc) Range\u003c\/th\u003e\n\u003cth\u003eFeed Rate (f) Per Revolution\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eCarbon Steel \/ Alloy Steel (HB180-280)\u003c\/td\u003e\n\u003ctd\u003e140 - 240 m\/min (459 - 787 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.05 - 0.18 mm\/rev (0.0020 - 0.0071 IPR)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStainless Steel Matrix (304, 316, 410)\u003c\/td\u003e\n\u003ctd\u003e100 - 160 m\/min (328 - 524 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.04 - 0.12 mm\/rev (0.0015 - 0.0047 IPR)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCast Iron Grades (GG20, GG25, GGG40)\u003c\/td\u003e\n\u003ctd\u003e110 - 180 m\/min (360 - 590 SFM)\u003c\/td\u003e\n\u003ctd\u003e0.05 - 0.20 mm\/rev (0.0020 - 0.0078 IPR)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c!-- Insert Purchase Internal Link Box --\u003e\n\u003cdiv style=\"border-style: dashed; background-color: #f4f4fa; text-align: center; padding: 15px;\" class=\"beyond-grid-box\"\u003e🔗 Need matching high-performance turning inserts?\u003ca href=\"https:\/\/cnchome-beyond.com\/search?q=TPMT1103\" target=\"_blank\" rel=\"noopener\"\u003e \u003cspan style=\"color: #47479f;\"\u003e\u003cspan style=\"text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e\u003cb\u003e\u003cu\u003eClick here to shop BEYOND Original TPMT 110304 \/ TPMT 110308 Carbide Inserts\u003c\/u\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/span\u003e \u003c\/a\u003ewith premium chipbreaker matrices.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- 4. Product Applications --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e4. Product Application Scenarios\u003c\/h2\u003e\n\u003cp\u003eThe robust 20mm left-handed geometry of the S20R-STFPL11 tool holder makes it highly effective for rigid internal processing across diverse turning operations:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSub-Spindle Back-Boring Operations:\u003c\/strong\u003e Essential for reverse spindle configurations on multi-axis turning centers where conventional right-handed bars do not offer correct toolpath geometry.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMedium-Sized Bore Internal Profiling:\u003c\/strong\u003e Offers ideal stiffness for roughing and finishing internal bores, ensuring tight tolerances without taper distortion.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy Duty Blind Hole Facing:\u003c\/strong\u003e The 91-degree approach profile executes clean perpendicular inner faces down to the center axis smoothly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- 5. Compatibility --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e5. Compatibility \u0026amp; Equipment Interface\u003c\/h2\u003e\n\u003cp\u003eThis 20mm round-shank boring bar fits directly into standard CNC lathe turret blocks, boring bar blocks, split bushings, or specialized tool holders. It interfaces seamlessly with precision CNC lathe systems and automated setups from leading global brands (including Haas, Mazak, Doosan, Citizen, Tsugami, and Fanuc). Optimized for left-handed tool orientations running rear or inverted turning cycles.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- 6. Material\/Grade Comparison (BEYOND Brand Internal) --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e6. BEYOND Premium Substrate \u0026amp; Grade Selection Matrix\u003c\/h2\u003e\n\u003cp\u003eTo maximize chip control and wear life, pair your S20R-STFPL11 boring bar with the corresponding BEYOND proprietary insert grade tailored to your target material:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBYM11 Grade (PVD Nano-Coated):\u003c\/strong\u003e Exceptional thermal shock resistance. Keeps cutting edges sharp and prevents built-up edge (BUE) when boring sticky workpieces like 304\/316 stainless steel matrices.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBYM25 Grade (CVD Multi-Layer Coated):\u003c\/strong\u003e Thick industrial wear barrier design. Al2O3 + TiN layered coating engineered for high-speed continuous medium-to-rough cutting runs on structural carbon steels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBYK15 Grade (Hardened Micro-Grain Substrate):\u003c\/strong\u003e Highly abrasion-resistant micro-grain layout, optimized for dry or wet high-velocity machining of abrasive grey and ductile cast iron parts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c!-- 7. Why Choose Us \u0026 Customer Reviews --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e7. Why Choose BEYOND Tooling Systems\u003c\/h2\u003e\n\u003cp\u003eAt BEYOND, we specialize in delivering high-tolerance cutting systems for demanding industrial settings. Every S20R-STFPL11 holder passes strict Coordinate Measuring Machine (CMM) checking procedures to guarantee insert pocket dimensional accuracy within ±0.01mm, ensuring exact repeatability across shifts.\u003c\/p\u003e\n\u003c!-- Customer Reviews Boxed Layout --\u003e\n\u003ch3 style=\"color: #47479f; margin-top: 20px;\"\u003eGlobal Machinist Field Reports:\u003c\/h3\u003e\n\u003cdiv class=\"beyond-review-container\"\u003e\n\u003cdiv class=\"beyond-review-card\"\u003e\n\u003cdiv class=\"beyond-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"Incredible Rigidity for Deep Internal Cuts\"\u003c\/strong\u003e\n\u003cp style=\"margin: 5px 0;\"\u003eSwitched to this S20R left-hand bar for our back-boring line on alloy steels. The 20mm steel body absorbs everything. TPMT 1103 inserts sit rock solid, and tool life has noticeably increased.\u003c\/p\u003e\n\u003cdiv class=\"beyond-review-meta\"\u003e— Marcus T., CNC Operation Lead (United States)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"beyond-review-card\"\u003e\n\u003cdiv class=\"beyond-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"Hervorragende Stabilität und Passform\"\u003c\/strong\u003e\n\u003cp style=\"margin: 5px 0;\"\u003eSehr präziser Drehmeißel für die Innenbearbeitung. Die Plattensitzgenauigkeit für TPMT 1103 ist phänomenal. Keine spürbare Vibration bei vollem Vorschub.\u003c\/p\u003e\n\u003cdiv class=\"beyond-review-meta\"\u003e— Juergen S., Senior Machinist (Germany)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"beyond-review-card\"\u003e\n\u003cdiv class=\"beyond-stars\"\u003e★★★★☆\u003c\/div\u003e\n\u003cstrong\u003e\"Ottimo corpo e finitura\"\u003c\/strong\u003e\n\u003cp style=\"margin: 5px 0;\"\u003eExcellent tool holder body finish. The screw lock provides a lower profile than traditional clamp styles, allowing chips to exit flawlessly from deep bores. Reliable product.\u003c\/p\u003e\n\u003cdiv class=\"beyond-review-meta\"\u003e— Alessandro V., Technical Workshop Manager (Italy)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"beyond-review-card\"\u003e\n\u003cdiv class=\"beyond-stars\"\u003e★★★★★\u003c\/div\u003e\n\u003cstrong\u003e\"20mmシャンクで抜群の安定性\"\u003c\/strong\u003e\n\u003cp style=\"margin: 5px 0;\"\u003e左勝手(L)のS20Rをサブスピンドル側で使用。剛性が非常に高く、削り出し加工でも寸法が一切ブレません。ポケット精度が高く、チップ交換時の微調整が不要になりました。\u003c\/p\u003e\n\u003cdiv class=\"beyond-review-meta\"\u003e— Sato H., Precision Components Engineer (Japan)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- 8. AI-Style FAQ (GEO\/AEO Structure) --\u003e\n\u003cdiv class=\"beyond-section\"\u003e\n\u003ch2\u003e8. Frequently Asked Questions (AI \u0026amp; Search Engine Optimized)\u003c\/h2\u003e\n\u003cdiv class=\"beyond-faq-item\"\u003e\n\u003cdiv class=\"beyond-faq-q\"\u003eQ: What is the minimum boring diameter for the S20R-STFPL11 tool holder?\u003c\/div\u003e\n\u003cdiv class=\"beyond-faq-a\"\u003eA: The absolute minimum bore diameter (D-min) for the S20R-STFPL11 is 25mm (0.9843 inches). Attempting to use this bar in smaller cavities will cause the heel of the steel shank to rub against the internal bore walls, destroying surface finish and causing tool failure.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"beyond-faq-item\"\u003e\n\u003cdiv class=\"beyond-faq-q\"\u003eQ: Can I use TPGT or TPMR inserts with this STFPL11 boring bar?\u003c\/div\u003e\n\u003cdiv class=\"beyond-faq-a\"\u003eA: Yes, as long as they follow the ISO 1103xx specification (e.g., TPGT 110304 or TPMR 110308) with an 11-degree positive relief angle. Ground inserts like TPGT work brilliantly for super-finishing non-ferrous parts, while TPMT is highly recommended for steel chip breaking.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"beyond-faq-item\"\u003e\n\u003cdiv class=\"beyond-faq-q\"\u003eQ: What is the maximum recommended overhang extension for a 20mm steel boring bar?\u003c\/div\u003e\n\u003cdiv class=\"beyond-faq-a\"\u003eA: For premium alloy steel shanks, standard engineering principles suggest a maximum overhang ratio of 3x to 4x the shank diameter. For a 20mm shank, keep the extension length extended out of the clamping block within 60mm to 80mm to avoid harmonic vibration marks.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Bottom Technical Panels (Grade Comparison, Troubleshooting, Matrix) --\u003e\n\u003cdiv class=\"beyond-footer-panel\"\u003e\n\u003ch3\u003eGrade Comparison, Troubleshooting Tips \u0026amp; Material Suitability Matrix\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eEquivalent Models Reference Cross-Guide:\u003c\/strong\u003e If you are converting older imperial workshop tooling layouts to metric industrial standards, this model effectively replaces American Standard designators like \u003cstrong\u003eS12R-STFPL3\u003c\/strong\u003e or custom 3\/4-inch heavy-duty internal boring configurations.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTroubleshooting Internal Turning Errors:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cem\u003eProblem - Chip Bird-Nesting \/ Compaction:\u003c\/em\u003e Switch from a 0.8mm nose radius insert to a sharper 0.4mm or 0.2mm configuration, and increase feed rate slightly to prompt clean chip fracturing against the built-in chipbreaker wall.\u003c\/li\u003e\n\u003cli\u003e\n\u003cem\u003eProblem - Accelerated Flank Wear:\u003c\/em\u003e Reduce your cutting surface speed (Vc) index or implement dedicated internal high-pressure coolant lines to stabilize thermal cycling at the edge.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eWorkpiece Material Suitability Matrix:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cdiv class=\"beyond-badge-container\"\u003e\n\u003cdiv class=\"beyond-badge\"\u003eP - Steel Alloys (Fully Optimized)\u003c\/div\u003e\n\u003cdiv class=\"beyond-badge\"\u003eM - Stainless Steel Matrices (Highly Suitable)\u003c\/div\u003e\n\u003cdiv class=\"beyond-badge\"\u003eK - Cast Iron Variants (Compatible Setup)\u003c\/div\u003e\n\u003cdiv class=\"beyond-badge\"\u003eN - Non-Ferrous Alloys (Excellent with Polished Inserts)\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"BEYOND","offers":[{"title":"Default Title","offer_id":43621453856940,"sku":"S20R-STFPL11","price":21.9,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0592\/7328\/1708\/files\/BEYOND_S20R-STFPL11_left_hand_internal_turning_tool_holder_20mm_steel_boring_bar_for_TPMT1103_carbide_inserts_CNC_lathe_medium_boring_operations.jpg?v=1780553502","url":"https:\/\/cnchome-beyond.com\/products\/beyond-s20r-stfpl11-boring-bar-holder-tpmt1103","provider":"CNCHome-Beyond","version":"1.0","type":"link"}