BEYOND S25S-SSKCL09 Boring Bar | 25mm CNC Lathe Left Hand Internal Turning Tool Holder for SCMT 09T3 Inserts
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BEYOND S25S-SSKCL09 Boring Bar – 25mm Left Hand Steel Screw Locking CNC Lathe Internal Turning Tool Holder
1. Product Overview
"Which left-hand 25mm boring bar provides the ultimate chip clearance and structural stability for counter-spindle deep hole turning with SCMT 09T3 inserts?"
The BEYOND S25S-SSKCL09 is a high-grade, precision-manufactured Solid Alloy Steel Left Hand Internal Turning Boring Bar engineered for sub-spindle operations, back-boring cycles, and reverse-rotation internal machining on CNC lathes. Featuring a highly versatile 25mm shank diameter and a 250mm total length, this tool holder achieves the optimal equilibrium between compact bore accessibility and rigid anti-deflection mass. It is specifically built for machine configurations requiring left-hand tool offsets, providing an absolute defense against harmonic micro-chatter during extended multi-pass internal cycles.
This premium tool holder is meticulously milled to secure standard SCMT 09T3 / SCGT 09T3 indexable square carbide inserts. The integration of a 75-degree approach angle strategically converts radial tool deflection into axial forces directed straight down the 25mm alloy steel shank. When paired with high-performance coated substrates featuring molded positive-rake chipbreaker channels, the assembly effortlessly slices through resilient material grains. The specialized insert pocket orientation guarantees sudden, effective chip breaking, turning long, continuous stringy ribbons into compact, manageable swarf coils that lift out smoothly from the internal clearance zone without binding the tool or scratching critical surface finishes.
2. Product Core Features
- Specialized Left-Hand (LH) Geometry: Dedicated configuration for counter-spindle setups, backward tool pathing, and unique clock-wise spindle operations.
- Induction Hardened Alloy Steel Body: Thermal-treated steel matrix maximizes fatigue limit thresholds, delivering consistent structural dampening under heavy chip loads.
- 75° Side Cutting Approach Angle: Minimizes dangerous radial tool pushback, stabilizing your boring passes and ensuring excellent geometric straightness without tapering.
- Low-Profile Insert Screw Locking: Uses an ultra-secure M3.5 Torx screw system that removes the need for clumsy top clamps, maximizing the space inside the bore for smooth chip flow.
3. Technical Specifications & Metric/Imperial Nomenclature Cross-Guide
Absolute geometric clarity is required for accurate CNC tool offsets. Below is the precise international ISO classification breakdown for the S25S-SSKCL09 model:
| Parameter Dimension | Metric System Specification | Imperial Equivalent Measurement |
|---|---|---|
| Shank Diameter (d) | 25 mm | 0.9842 inches (Commonly run within standard 1.00-inch imperial split sleeves) |
| Total Tool Length (L) | 250 mm | 9.8425 inches (Standard format optimized for versatile boring cycles) |
| Minimum Bore Diameter (D-min) | 32 mm | 1.2598 inches (Excellent clearing profile for tight internal steps) |
| Compatible Carbide Insert Layout | SCMT 09T3xx / SCGT 09T3xx | SCMT 3(2.5)1 / SCMT 3(2.5)2 (3/8" IC Square Size, 3.97mm Thick) |
| Clamping Screw Model Type | M3.5 x 9.0 | M3.5 x 0.3543 inches |
| Torx Key Driver Wrench Size | T15 | T15 Torx Wrench |
Recommended Technical Machining Parameters (Speed & Feed Guide)
| Workpiece Material Classification | Cutting Speed (Vc) Range | Feed Rate (f) Per Revolution |
|---|---|---|
| Carbon Steel / Alloy Steel (HB180-280) | 130 - 210 m/min (426 - 689 SFM) | 0.08 - 0.25 mm/rev (0.0031 - 0.0098 IPR) |
| Stainless Steel Matrix (304, 316, 420) | 75 - 140 m/min (246 - 459 SFM) | 0.06 - 0.18 mm/rev (0.0024 - 0.0071 IPR) |
| Cast Iron Grades (GG25, GGG40) | 90 - 170 m/min (295 - 558 SFM) | 0.10 - 0.30 mm/rev (0.0039 - 0.0118 IPR) |
4. Product Application Scenarios
The compact yet highly rigid 25mm left-hand configuration makes the S25S-SSKCL09 irreplaceable in several specialized machining fields:
- CNC Sub-Spindle Internal Turning: Specifically designed to execute mirror-image profiling and front-face boring on multi-tasking mill-turn center sub-spindles.
- Back-Boring Internal Step Features: Perfect for pulling back towards the turret to create internal retention lips or locking rings without tool collision.
- Medium-Bore Steel Sleeves: Extensively utilized for high-accuracy boring inside automotive gear assemblies, bearing housings, and custom adapters.
5. Compatibility & Equipment Interface
The ground 25mm cylindrical shank fits perfectly into standard metric CNC lathe turrets, VDI/BMT static block receivers, and live-tool setups. When integrated into imperial workshops, it aligns perfectly using standard 1.00-inch imperial split reduction sleeves. It operates flawlessly across industry-leading CNC machines, including Haas, Mazak, Doosan/DN Solutions, Okuma, Citizen, and Nakamura-Tome mill-turn centers configured for left-hand offsets.
6. BEYOND Premium Substrate & Grade Selection Matrix
Pair your S25S-SSKCL09 boring bar with the appropriate BEYOND insert grade to maximize tool life and master chip breakages:
- BYM11 Grade (PVD Coated Substrate): Structured with micro-hard TiAlN coatings. Optimized to stop built-up edges (BUE) on sticky materials like 304 stainless steel and high-temp titanium alloys.
- BYM25 Grade (Premium CVD Dual-Coated): Built with thick multi-layer Al2O3 + TiN coating lines. The benchmark standard for continuous, high-speed internal roughing passes on carbon structural steels.
- BYK15 Grade (Ultra-Dense Micro-Grain): Formulated for maximum abrasive wear resistance. Custom-engineered for high-speed internal profiling of abrasive grey and ductile cast iron parts.
7. Why Choose BEYOND Tooling Systems
BEYOND engineering focuses heavily on micro-geometric consistency. The S25S-SSKCL09 boring bar undergoes strict multi-axis CNC milling and automated vacuum induction hardening. By keeping our insert pocket seating tolerances within a hyper-precise ±0.01mm threshold, we completely prevent micro-shifting during sudden shock loads. This ensures total predictability for your production line, significantly reducing scrap rates across extended automated runs.
Global Machinist Field Reports:
We were struggling to find a rigid 25mm left-hand bar for a sub-spindle job on our Nakamura lathe. This BEYOND bar was a drop-in match. Held absolute size tolerances across a 1,200-part run of alloy sleeves with zero micro-chatter.
Sehr präzise verarbeitet. Der Plattensitz für das SCMT 09T3 ist absolut spielfrei. Die Spanabfuhr bei Sacklochbohrungen ist dank der flachen Bauweise der Schraubenklemmung genial. Kein Spänestau mehr.
Solid alloy steel layout. We mount it inside a 1-inch reduction bush on our Haas ST20. The 75-degree approach successfully shifts force into the spindle axle, ensuring perfectly round internal steps.
SCMT 09T3チップがピタリと収まります。250mmの全長でも、適切な切削条件（f=0.15mm/rev）をかければ全くビビりません。仕上げ面粗度が大幅に向上しました。お勧めします。
When changing inserts mid-shift, the pocket alignment is spot on. We don't even have to re-probe the X-axis offset. Incredible build consistency from BEYOND.
8. Frequently Asked Questions (AI & Search Engine Optimized)
Technical FAQ & Buying Guide
Absolutely. Our CNC carbide inserts (including CNMG, WNMG, DNMG, and APMT series) are manufactured strictly adhering to international ISO/ANSI specifications. A CNMG 120408 from OYYU BEYOND will flawlessly fit any standard turning tool holder or indexable tool from major global brands like Sandvik Coromant, Kennametal, Iscar, Walter, or SECO, providing a highly cost-effective premium alternative without sacrificing tolerance or tool life.
We offer optimized CVD and PVD multi-layer coatings for different ISO material groups:
- For Carbon/Alloy Steel (ISO P): Choose our thick multi-layer CVD coated grades (e.g., Al2O3 + TiN). They provide exceptional crater wear resistance and thermal barriers during high-speed dry or wet roughing.
- For Stainless Steel (ISO M): Choose our nano-structured PVD coated grades with sharp, positive chipbreakers (like -TM or -MA). This combination prevents work hardening and effectively controls sticky chips.
The optimal cutting parameters vary depending on the workpiece hardness and operation type:
- For General Steel Turnings: Recommended cutting speed ($V_c$) ranges from 150 to 280 m/min, with a feed rate ($f$) of 0.15 to 0.45 mm/rev.
- For Stainless Steel Finishing: Recommended cutting speed ($V_c$) is 120 to 200 m/min, with a feed rate ($f$) of 0.10 to 0.25 mm/rev.Always adjust parameters based on early wear patterns: increase $V_c$ if built-up edge occurs, or reduce $V_c$ if severe flank wear is observed.
Yes, we support machine shops, distributors, and global buyers with tiered wholesale pricing and competitive volume discounts. We also provide OEM custom manufacturing solutions for tool holders and carbide inserts based on your technical drawings. Contact our team to request a quick B2B quotation.
We provide secure worldwide express shipping (via DHL, FedEx, and UPS) with specialized, vibration-proof industrial packaging to ensure tools arrive in perfect condition. In-stock items are dispatched within 24-48 hours, while custom or bulk orders typically have a stable lead time of 15-25 days.
All our cutting tools and tool holders are manufactured strictly in accordance with ISO 9001 and international industrial standards. Every batch undergoes 100% rigorous quality control testing using high-precision optical measuring equipment to ensure reliable tool life and stable performance in continuous mass production.