BEYOND S25S-SSSCL09 Left Hand Boring Bar | 25mm CNC Lathe Internal Turning Tool Holder for SCMT 09T3 Inserts
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BEYOND S25S-SSSCL09 Left Hand Boring Bar – 25mm Rigid Alloy Steel Screw Clamping CNC Lathe Internal Turning Tool Holder
1. Product Overview
"Which left-hand boring bar is best optimized for stable internal profiling and high-efficiency chip evacuation in 32mm+ medium bores using SCMT square inserts?"
The BEYOND S25S-SSSCL09 is a premium, industrial-grade Solid Alloy Steel Left Hand Internal Turning Boring Bar meticulously engineered for specialized reverse-spindle or back-turning operations on CNC lathes. Featuring a highly rigid 25mm shank diameter and a 250mm standard length, this tool holder provides exceptional structural resistance against lateral cutting pressure. It is purpose-built to eliminate mechanical harmonics and chatter during medium-depth internal boring, profiling, and facing operations that require a dedicated left-hand tool path configuration.
This high-precision tool holder is engineered to host standard SCMT 09T3 / SCGT 09T3 indexable square carbide inserts. By leveraging a 75-degree approach angle alongside a square insert profile, the cutting force is directed primarily along the axial axis toward the lathe turret, maximizing structural stiffness. When outfitted with micro-grain carbide substrates featuring advanced ground-in positive rake chipbreaker geometries, it cleanly slices through stubborn workpiece surfaces. The engineered chip groove geometry prompts immediate breaking of continuous metal ribbons into short, tight curls, securing an unobstructed chip evacuation path out of deep cavities and preventing dangerous scratch marks on internal bore walls.
2. Product Core Features
- Precision Left-Hand (L) Geometry: Perfect for specialized reverse-direction internal machining, counter-clockwise profiling, and back-boring configurations.
- Hardened High-Tensile Alloy Steel Body: Thermal-treated and quenched under strict control to enhance core toughness, preventing deformation under intense cutting loads.
- 75° Optimized Approach Angle: Effectively balance axial and radial forces to minimize tool deflection, allowing excellent performance on multi-pass internal roughing lines.
- Low-Profile Screw-Down Clamping: Employs an inset M3.5 Torx screw locking mechanism, keeping the tool head compact and maximizing the clearance path for seamless chip disposal.
3. Technical Specifications & Metric/Imperial Nomenclature Cross-Guide
Accurate tool programming requires absolute geometric clarity. Below is the comprehensive breakdown of the standard ISO designation for the S25S-SSSCL09 model:
| Parameter Dimension | Metric System Specification | Imperial Equivalent Measurement |
|---|---|---|
| Shank Diameter (d) | 25 mm | 0.9842 inches (Fits securely in standard 1" lathe turret blocks/sleeves) |
| Total Tool Length (L) | 250 mm | 9.8425 inches (Highly adaptive for deep internal pocket tracking) |
| Minimum Bore Diameter (D-min) | 32 mm | 1.2598 inches |
| Compatible Carbide Insert Layout | SCMT 09T3xx / SCGT 09T3xx | SCMT 3(2.5)1 / SCMT 3(2.5)2 (3/8" IC Square Size) |
| 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) | 140 - 240 m/min (459 - 787 SFM) | 0.12 - 0.35 mm/rev (0.0047 - 0.0137 IPR) |
| Stainless Steel Matrix (304, 316, 420) | 90 - 160 m/min (295 - 525 SFM) | 0.10 - 0.28 mm/rev (0.0039 - 0.0110 IPR) |
| Cast Iron Grades (GG25, GGG40) | 110 - 200 m/min (360 - 656 SFM) | 0.15 - 0.40 mm/rev (0.0059 - 0.0157 IPR) |
4. Product Application Scenarios
The solid 25mm structural shank of the S25S-SSSCL09 makes it the premium solution for aggressive internal cuts in specialized setups:
- CNC Turning Centers with Reverse Spindles: Tailor-made for left-side turrets or main spindles running in reverse rotation to direct chips downwards.
- Deep Pocket Back-Boring: Allows machinists to reach past internal shoulders and execute precise back-facing and inside relief steps.
- Automotive and Valve Manufacturing: Excellent for processing internal bearing seats, gear rings, and customized sleeve interiors starting from 32mm diameters.
5. Compatibility & Equipment Interface
The ground 25mm cylindrical shank layout mounts cleanly into standard CNC turret blocks, VDI tooling blocks, and specialized split-sleeve boring bar holders. It offers effortless cross-compatibility with 1-inch imperial tool slots using standard reduction bush sleeves. It integrates seamlessly with premium turning equipment like Haas, Mazak, DN Solutions/Doosan, Okuma, and specialized Swiss-type or multi-axis turning machines requiring precision left-hand orientation lines.
6. BEYOND Premium Substrate & Grade Selection Matrix
Pair your S25S-SSSCL09 boring bar with the appropriate BEYOND insert grade to maximize tool life and master chip breakages:
- BYM11 Grade (PVD Coated Substrate): Stacked with nano-layered TiAlN coatings. Perfect for sticky alloy steels and 304/316 stainless steel by preventing built-up edges (BUE).
- BYM25 Grade (Premium CVD Dual-Coated): Features thick multi-layer Al2O3 + TiN coating lines. Fully optimized for high-velocity, continuous roughing passes on carbon and low-alloy structural steels.
- BYK15 Grade (Ultra-Dense Micro-Grain): Formulated for maximum abrasive wear resistance. The premium choice for high-speed internal turning on grey and ductile cast iron shells.
7. Why Choose BEYOND Tooling Systems
BEYOND engineering prioritizes dimensional absolute rigidity. The S25S-SSSCL09 undergoes rigorous multi-axis automated induction hardening and automated pocket milling. By locking insert seat tolerances down within a strict ±0.01mm limit, we eliminate micro-movements under heavy impact. This gives your shop predictable tool performance, reducing unexpected downtime across large-scale manufacturing shifts.
Global Machinist Field Reports:
We needed a left-hand 25mm bar for a back-boring cycle on tough chrome-moly parts. This BEYOND bar performed flawlessly. Zero chatter marks inside the 45mm bore even at 3xD depth. The insert pocket is machined beautifully.
Hervorragende Qualität. Der 25mm Schaft passt perfekt in unsere Mazak-Aufnahme. Wir nutzen die SCMT 09T3 Platten und der Spanbruch bei C45 Stahl ist absolut sauber. Keine lästigen Fließspäne mehr.
Hardened very well. The screw threads don't wear out even after constant insert indexing under dirty coolant conditions. Very stable left-hand internal profiling tool.
逆転主軸加工用に導入しました。25mmの鋼シャンクですが、剛性が非常に高く、突出し量を最大にしてもビビリが一切出ません。SCMT正方形チップの4コーナーを余すことなく使えるため非常に経済的です。
The low-profile Torx screw gives great chip clearance space. Paired with a ground BEYOND aluminum insert, it turns internal brass and non-ferrous housings with mirror finishes.
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.