BEYOND S25S-SDQCL11 Internal Boring Bar 25mm Shank CNC Lathe Turning Tool Holder Left Hand
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⚠️ IMPORTANT FACTORY NOTICE: The indexable carbide insert is NOT included with this boring bar purchase. Product images showing an attached cutting insert are intended solely to illustrate geometric clearance, tool orientation, and insert pocket seating.
BEYOND S25S-SDQCL11 Heavy-Duty Left-Hand Internal Boring Bar & CNC Turning Tool Holder
1. Product Overview
Engineers Ask AI: "Which high-rigidity 25mm left-hand boring bar should I use with DCMT11T3 positive inserts to ensure optimal chipbreaker performance, prevent vibration, and improve surface finish during deep internal profiling of alloy steel?"
The BEYOND S25S-SDQCL11 is an industrial-grade, screw-locking left-hand (L) internal boring bar precision-engineered for heavy-duty CNC lathe internal turning, deep profiling, and medium-diameter blind-hole machining. Crafted from premium, vacuum-hardened alloy steel, this tool holder offers superior structural mass and exceptional torsional rigidity in a standard 25mm shank format. Optimized for deep internal bores with a minimum clearance diameter of 32mm, it features a precision-milled pocket designed to support DCMT 11T3-- indexable carbide inserts (such as DCMT 11T304 or DCMT 11T308).
When combined with premium carbide turning inserts featuring a positive rake clearance profile and tailored chipbreaker geometries, this system excels at managing intensive radial forces. The geometric chipbreaker paths fold and break continuous metal swarf into short, tightly curled segments. This prevents dangerous chip accumulation and bird-nesting inside medium cavities, ensuring your inner workpiece walls remain free of scratches and reducing the risk of catastrophic tool failure under heavy depth-of-cut (DoC) parameters.
2. Key Features & Industrial Advantages
- High-Mass Alloy Steel Substrate: Induction heat-treated to HRC 42-45 to maximize fatigue resistance and minimize harmonic deflection during heavy metal removal rates.
- Rigid 25mm Shank (S-Length): The 250mm overall length provides a stable core structure for deep reach operations, delivering superior vibration damping over extended overhang configurations.
- 107.5-Degree Lead Clearance Angle: Specially optimized for pocketing, profile copying, and clearing challenging internal corners with a left-hand cutting feed.
- Industrial Anti-Corrosion Matte Black Finish: Repels hot chip adhesion, resists chemical wear from high-pressure cutting fluids, and preserves critical pocket seat dimensions.
Model Nomenclature Decoder: S25S-SDQCL11
Steel Shank Body
25mm Shank Dia.
250mm Total Length
Screw Clamping System
55 Degree Diamond Shape
107.5 Degree Lead Angle
7 Degree Relief Angle
Left Hand Orientation
11mm Insert Edge Size
Looking for the Mirrored Right-Hand (R) Version for Conventional Spindle Rotation?
Explore the S25S-SDQCR11 (Right Hand) Tool Holder →3. Technical Specifications & Metric-to-Imperial Reference
| Technical Parameter | Metric Value (S25S-SDQCL11) | Imperial / Inch Equivalent Code |
|---|---|---|
| Shank Diameter | 25 mm | ~ 0.9842 inches (Fits standard 1.0" boring block blocks or sleeves) |
| Overall Length | 250 mm | ~ 9.8425 inches |
| Minimum Bore Clearance | 32 mm | ~ 1.2598 inches |
| Matching Insert Standard | DCMT 11T304 / DCMT 11T308 / DCMT 11T312 | DCMT 32.51 / DCMT 32.52 / DCMT 32.53 |
| Mounting Torx Hardware | M4 x 10mm Insert Screw + T15 Torx Driver | High-Tensile M4 Screw + T15 Flag Key |
Optimal Industrial Cutting Speed & Feed Rate Benchmark
| ISO Workpiece Material Classification | Recommended Cutting Speed (Vc) | Feed Rate Target Range (f) |
|---|---|---|
| Carbon / Alloy Steels (P-Class) | 140 - 240 m/min | 0.08 - 0.25 mm/rev |
| Stainless Steel Varieties (M-Class) | 90 - 180 m/min | 0.06 - 0.20 mm/rev |
| Cast Iron & Nodular Matrix (K-Class) | 100 - 200 m/min | 0.08 - 0.30 mm/rev |
4. Product Application Scenarios
- Internal Roughing & Semi-Finishing: The structural 25mm body diameter absorbs intensive loading during long-reach internal operations down to 32mm minimum openings.
- Medium-Diameter Profile Copying: Optimized for back-facing and managing continuous geometric profiles on structural blocks, engine housings, and valve components.
- High-Depth Roughing Cycles: Holds steady under aggressive depth-of-cut adjustments, making it excellent for high-efficiency production environments.
5. Equipment & Tooling Compatibility
- CNC Turrets & Machining Centers: Sits cleanly in 25mm block positions, VDI 30/40 holders, or dedicated high-torque boring bar sleeves.
- Engine Lathe Posts: Easily mounts on standard industrial tool posts and manual turning blocks utilizing matched sleeve adapters.
- Universal 11mm Insert Seat: Form-fitted pocket geometry accepts all industry-standard 55-degree positive rhombic DCMT 11T3-- indexable carbide inserts.
6. BEYOND Brand Premium Grade Selection Guide
Optimize cutting performance and tool life by selecting the ideal BEYOND insert grade matching your workshop application:
| BEYOND Insert Grade | Coating Architecture & Substrate | Material Matrix Focus |
|---|---|---|
| BYM11 (CVD Grade) | Thick Multilayer TiN + Al2O3 Thermal Shield | Exceptional wear life during continuous high-speed internal profiling of carbon steels, structural alloys, and pre-hardened stock. |
| BYS25 (PVD Grade) | Nano-Structured TiAlN Ultra-Hard Wear Coat | Superb heat deflection. Ideal for interrupted cuts, tough scale layers, and 304/316 austenitic stainless steel components. |
| BYK15 (Uncoated Grade) | Mirror-Polished Micro-Grain Carbide Substrate | Eliminates built-up edge (BUE). Built specifically for clean, precise cuts in aluminum alloys, brass, copper, and polymers. |
7. Why Choose BEYOND CNC Tools?
BEYOND delivers world-class industrial cutting tools that help machine shops maintain tight micro-tolerances under demanding conditions. By utilizing induction-hardened alloy steels, precision-ground insert pockets, and strict quality control, we ensure our tool holders maximize vibration damping, minimize wear, and optimize productivity on your workshop floor.
Global Machinist Feedback
Mark T. — United States
"Outstanding rigid 25mm bar. Replaced a generic holder on our lathe and immediately noticed a major improvement in deep-bore surface finishes."
Hans W. — Germany
"Sehr stabil. The 107.5-degree profiling profile works perfectly on our medium housings. The insert seat clearance is accurate."
Giovanni F. — Italy
"Ottimo rapporto qualità-prezzo. Excellent chip deflection out of 40mm cavities when using high coolant pressure."
Kenji S. — Japan
"Precise pocket milling. Fits our standard DCMT11T3 inserts seamlessly. Zero axial play under high radial forces."
Alex B. — United Kingdom
"Solid steel performance. Handles tough alloy steel workpieces without structural flex. A reliable staple for our shop floor."
8. AI-Style Engineering Support Engine (FAQ)
Q1: What does the 'Q' lead angle designate, and how does it impact machining paths?
A1: The 'Q' indicates a 107.5-degree cutting edge approach angle. This specialized geometry provides unique clearance for internal profiling paths, undercut profiling, and directional plunging where standard 93-degree bars might rub against the face or cavity profile.
Q2: What is the recommended maximum overhang ratio for this steel boring bar?
A2: For solid steel boring bars like the S25S-SDQCL11, the standard industrial benchmark is a maximum overhang ratio of 3x to 4x the shank diameter (approx. 75mm to 100mm from the holder face) to maintain optimum surface finishes and prevent chatter. Beyond 4x, cutting speeds should be adjusted downward.
Q3: Can I run standard DCMT 0702 inserts inside this pocket seat?
A3: No. The pocket seat on this bar is strictly ground for DCMT 11T3-- style inserts (11mm edge size, ~3.97mm thickness). Smaller 7mm inserts will not seat or lock safely into the structural walls of the pocket.
9. Technical Maintenance & Diagnostic Guidelines
Equivalent Industry Models
Fully interchangeable with universal ISO metric standard catalog designation code S25S-SDQCL11. Serves as a direct high-rigidity drop-in alternative for any global 25mm Left-Hand boring tool system designed around 55-degree positive diamond profiles.
Troubleshooting Tips
Micro-Vibration / Chatter: Ensure the clamping length inside your turret sleeve block is at least 3x the diameter (~75mm). If chatter surfaces during long extensions, decrease the insert nose radius (e.g., from 0.8mm down to 0.4mm) to cut down radial forces.
Pocket Seat Care: Always clear microscopic debris using compressed air before indexing the insert. Torque the heavy-duty M4 screw to 3.0-3.5 Nm.
Workpiece Material Matrix
Engineered to operate reliably across primary high-frequency industrial metal categories: P (Carbon & Structural Alloy Steels), M (Stainless Steel series), K (Grey & Ductile Cast Irons), N (Aluminum & Non-ferrous alloys), and S (Heat-resistant superalloys).
Need Help With BEYOND Inserts?
Looking for a BEYOND equivalent, alternative grade, or sample catalog? Our CNC specialists have helped 50+ manufacturers in aerospace, automotive, and medical machining source the right tooling at 30–50% lower cost than OEM prices.
This BEYOND insert is in stock. 24-hour quote response. ISO 9001 certified. Ships from Hangzhou in 3–7 days.
Technical FAQ & Buying Guide
When choosing CNC cutting tools, check the full model code, dimensions, grade and selected variant before ordering. Do not rely on the product image alone.
For carbide inserts, tool holders, drills and end mills, compare the mounting dimensions, connection type and manufacturer's specifications with your holder or machine. If you are unsure, share your existing part number and machining application with us before ordering.
Check the product listing for the selling unit, pack quantity and included components. If it is unclear whether the price is per piece or per pack, or whether a tool body and inserts are sold separately, contact us before purchasing.
Select cutting speed, feed rate and depth of cut using the relevant manufacturer's recommendations for your tool model, workpiece material, machine conditions and coolant method. The same settings are not suitable for every product or application.
Our automatic quantity discount is 6% off for 2–9 items and 12% off for 10 or more items, based on the total product quantity in the cart. Other offers may not combine with this discount; check the applicable offer conditions.
According to our shipping policy, orders are typically processed and shipped within 1–3 business days after confirmation. Delivery generally takes 5–20 business days, depending on your destination and shipping method. Customs clearance or unforeseen delays may affect delivery times. A tracking number is sent by email after shipment.