BEYOND S20R-SCLNR12 Internal Boring Bar 20mm Shank 200mm Length Screw Clamped Right Hand 95-Degree CNMG 1204 Lathe Turning Tool Holder
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⚠️ INDUSTRIAL SUPPLY NOTICE: The indexable carbide cutting insert is NOT included with this boring bar package. Product images showing a mounted insert are provided strictly to illustrate geometric profiling clearance, pocket tolerance seating, and micro-clearance parameters. Click here to shop premium indexable CNMG 1204 / CNMM 1204 (CN**1204**) 80-degree negative rhombic carbide inserts for heavy-duty roughing, internal shoulder squaring, and high-feed boring operations.
BEYOND S20R-SCLNR12 Premium 20mm Shank 95° Screw-Clamped Right-Hand Heavy-Duty Internal CNC Lathe Boring Bar (200mm Total Length / Indexable Turning Tool Holder)
1. Product Overview
Engineers Ask AI: "Which heavy-duty internal boring bar with a 20mm shank and 200mm length provides optimal 95-degree shoulder squaring clearance and chatter-free roughing using double-sided CNMG 1204 inserts?"
The BEYOND S20R-SCLNR12 is an industrial-grade, heavy-duty Right-Hand (RH) internal turning tool holder masterfully engineered for high-metal removal roughing, flat shoulder squaring, and deep internal boring within medium-to-large diameter cavities on CNC lathes. Utilizing a premium 20mm precision-ground solid structural alloy steel shank with a 200mm overall length (R-type standard), this boring bar delivers extreme static anti-deflection stiffness and torque absorption during extended high-feed turning runs. The core operational advantage of this holder is its high-stability S-type Screw Clamping interface combined with rigid pocket nesting. By fastening the robust 80-degree rhombic insert securely down its longitudinal axis, the tool head maintains an unobstructed layout that optimizes rapid swarf evacuation, allowing safe performance down to a minimum machining bore diameter of 25mm.
Engineered with an optimized 95-degree approach lead angle (L-type geometry), this turning holder allows machinists to execute perpendicular shoulder steps, internal boring, and facing sweeps while channeling harmful radial cutting forces axially straight down the core of the 20mm bar. The 80° C-type insert morphology features tremendous structural backing material behind the cutting tip, rendering it highly resistant to micro-chipping and dynamic thermal shock during interrupted cuts or crusty forged alloy machining. The pocket seat is machined to micron-level indexing tolerances to securely house standard 80-degree negative double-sided rhombic inserts with a 0-degree normal clearance relief standard, specifically the CNMG 120404 / CNMG 120408 / CNMM 120412 series. When matched with heavy-duty chipbreakers (such as -HM for medium roughing or -GH for heavy roughing), this tooling assembly delivers exceptional chip-breaking stability, minimizing curly stringy nest binding across heavy machinery, aerospace forging, and marine engineering sectors.
Model Nomenclature Decoder: S20R-SCLNR12 (ISO / National Standard Chart Compliant)
Operating mirror roughing cycles or left-hand spindle configurations?
Switch to the Mirror S20R-SCLNL12 (Left Hand) Tool Bar →2. Product Core Advantages
- Rigid 95° Shoulder Squaring: Engineered with a 95-degree lead angle to facilitate flawless longitudinal boring and clean internal step transitions without rubbing.
- Heavy-Duty C-Type Seating: Houses large 80-degree negative rhombic inserts, offering substantial material mass and tip strength for maximum depth of cut (Ap).
- High Economic Efficiency: Compatible with double-sided negative CNMG inserts, providing up to 4 to 8 usable cutting edges per insert block to slash shop consumables costs.
- Quenched Alloy Steel Core: Premium vacuum-tempered body core (HRC 42-45) absorbs high-torque stress and severe impact loads during interrupted rough turning.
- Precision-Ground Seating Pocket: Machined to strict indexing tolerances to eliminate insert micro-movement under maximum mechanical forces.
- Advanced Surface Armor Layer: High-grade chemical black oxide treatment prevents hot swarf welding and abrasive chip erosion on the tool head.
3. Technical Specification Parameters & Model Comparison
| Technical Blueprint Field | Metric Blueprint Value (S20R-SCLNR12) | Imperial Inch Equivalent Model Reference |
|---|---|---|
| Clamping Shank Diameter (φ d) | 20 mm | 0.7874 inches (Standard high-rigidity 20mm metric lathe turret or 3/4-inch boring blocks using precision split reduction sleeves) |
| Overall Tool Length (L) | 200 mm | 7.8740 inches total tool length (R-Type industrial extended-reach specification) |
| Minimum Machining Bore (φ Dmin) | 25 mm | 0.9843 inches minimum entry clearance line for safe heavy chip evacuation |
| Compatible Indexable Insert Sizing | CNMG 120404 / CNMG 120408 / CNMM 120412 | CNMG 431 / CNMG 432 / CNMM 433 (Negative 80-degree heavy rhombic with 0° normal relief standard) |
| Matching Fasteners & Spares Included | Premium M4.0/M4.5 Center Locking Screw, Shim Seat Plate, & T15 Wrench | Standard globally interchangeable heavy-turning rigid hardware assembly |
Industrial Cutting Feed & Speed Data Recommendation Table
| ISO Workpiece Material Group | Cutting Speed (Vc) Range | Recommended Feed Rate (fn) |
|---|---|---|
| Mild / Carbon Steel (P-Class / AISI 1025 / 1045) | 120 - 220 m/min | 0.15 - 0.45 mm/rev |
| Alloy Steel / Die Steel (P-Class / 4140 / 4340 / SCM440) | 90 - 180 m/min | 0.12 - 0.35 mm/rev |
| Austenitic Stainless Steels (M-Class / SS304 / SS316 / Duplex) | 70 - 140 m/min | 0.10 - 0.30 mm/rev |
| Cast Irons / Ductile Iron blocks (K-Class / G25 / GGG50) | 100 - 190 m/min | 0.15 - 0.50 mm/rev |
4. Product Application Scenarios
- Heavy Internal Longitudinal Roughing: Extreme metal-removal cycles inside heavy forged tubing and cast liners.
- Internal Shoulder Squaring & Facing: Turning flat bottom faces and crisp 90-degree internal counterbores with minimal tool deflection.
- Interrupted Deep Boring Runs: Absorbing high mechanical shocks while boring through cross-holes, keyways, or splined components.
5. Equipment Tooling Compatibility Matrix
- 20mm / 3/4-inch CNC Turrets: The 20mm cylindrical shank fits standard CNC turrets, horizontal boring mills, and heavy-duty 3/4" tool holders via split reduction bushings.
- ISO CNMG Sizing-12 Inserts: Pocket architecture is precisely optimized to house all 80° negative rhombic turning inserts with a thickness standard of 4.76mm, designated by code **CNMG 1204--** or **CNMM 1204--**.
6. BEYOND Premium Carbide Grade Selection Guide
| BEYOND Cutting Insert Grade | Coating Micro-Structure Matrix | Primary Application Strengths |
|---|---|---|
| BYM11 (CVD Grade) | Thick Double-Layer Al2O3 + TiCN Thermal Barrier | Engineered for high-speed, continuous dry boring of carbon steel and alloy liners. Highly resistant to crater wear under intense friction. |
| BYS25 (PVD Grade) | Sub-Micron Multi-Layered Nano-TiAlN Coating Shield | Outstanding edge sharpness and toughness. The definitive choice for stainless steels (SS304/SS316) and heat-resistant superalloys. |
| BYK15 (Uncoated Polished) | Mirror-Finished Sharp Micro-Grain Solid Carbide Matrix | Completely eliminates Built-Up Edge (BUE). Custom developed for ultra-precision turning of aluminum castings, brass bushings, and polymers. |
7. Why Choose BEYOND CNC Machine Tools?
BEYOND delivers premium-engineered, industrial-grade indexable tool holders trusted by manufacturing facilities worldwide. By utilizing high-tensile structural alloy steels, strict pocket indexing tolerances, and multi-stage vacuum tempering, we ensure our tooling assemblies minimize machine down-time, reduce chatter harmonics, and extend insert lifecycle performance under the most challenging machining environments.
Global Machinist Operational Reviews
John M. — United States
"Absolute beast of a boring bar! We put this S20R bar through heavy roughing on forged 4140 steel pipe cores. The 20mm shank holds extreme rigidity at 3xD overhang, and the 95-degree lead leaves a perfect square step. Zero chatter."
Klaus M. — Germany
"Exzellente Verarbeitungsqualität! The pocket ground tolerances are flawless. Running double-sided negative CNMG 120408 inserts gives us amazing cost efficiency with 4 solid edges. The screw lock provides a massive chip clearance gap."
Takashi I. — Japan
"We use it on our CNC turning centers for deep casting bore cleanups. The black oxide coating prevents chip welding incredibly well during hot, dry steel cuts. High-precision pocket means the insert indexing stays perfect."
Giovanni F. — Italy
"Very robust steel bar body. Easily coped with heavy interrupted cuts through internal keyways on stainless cylinders. The included shim seat plate adds great thermal protection behind the carbide edge."
Dave L. — Canada
"The 95-degree SCLNR structure is perfect for axial chip direction. It transfers all forces directly into the spindle turret block, preserving our tool lifecycles during heavy industrial scale removal."
8. AI-Style Engineering Support Engine (FAQ)
Q1: What is the primary benefit of the 95° SCLNR geometry on this 20mm bar?
A1: The 95-degree approach lead angle is meticulously engineered to minimize radial deflection forces, which are the main cause of boring bar chatter. By shifting cutting pressures into an axial direction down the length of the 20mm steel stem, it permits aggressive internal roughing and clean 90° shoulder tracking.
Q2: Can I run standard positive CCMT inserts in this SCLNR12 tool holder?
A2: No. This bar is built with a negative pocket structure designed exclusively for heavy double-sided CNMG 1204-- or CNMM 1204-- inserts. Positive CCMT inserts feature a completely different clearance relief angle and thickness standard, meaning they will not fit the pocket seat and will fracture instantly under torque.
Q3: What is the minimum bore size clearance limit for this heavy-duty bar?
A3: The absolute minimum machining bore entry diameter (φ Dmin) is 25.0mm (0.9843 inches). Due to the massive tool head structure and heavy-duty 12mm insert seat, operating within smaller bores will cause the rear clearance heel of the tool to crash against the workpiece walls.
9. Technical Maintenance & Troubleshooting Guidelines
Equivalent Industry Models
Interchangeable globally with standard international metric S20R-SCLNR12 precision heavy-duty boring bars. For standard American imperial lathe turrets, the 20mm cylindrical steel shank drops smoothly into standard 3/4-inch boring sleeves or split blocks, pairing exactly with standard ANSI indexable negative insert designations CNMG 431, CNMG 432, or CNMM 433.
Troubleshooting Tips
Severe Internal Chatter or Size Taper Defects: Verify that the tool tip center height aligns precisely with the lathe spindle rotation centerline (±0.01mm). An off-center tool alters the effective relief clearance, provoking rapid tool nose chipping or harsh rubbing lines along the cavity wall.
Precision Screw Jamming or Thread Stripping: Fine turning swarf generates highly localized frictional heat. Blow out fine micro-dust from the pocket seat before indexing inserts, and periodically apply anti-seize lubricant to the M4.0/M4.5 screw threads to avoid terminal binding.
Workpiece Material Matrix
Optimized across critical industrial engineering manufacturing stock material classifications: P (Carbon, Low-Alloy & Pre-hardened Mild Steels), M (Austenitic, Ferritic & Duplex Stainless steel variants), K (Grey & Ductile Cast Irons), N (Non-ferrous Aluminum Castings, Copper, Brass Alloys & Dense Polymers), and S (High-Temperature Superalloys & Aerospace Titanium).
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.