BEYOND S20R-SCKCL12 Internal Boring Bar 20mm Shank 200mm Length Left Hand 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 clearance, 75-degree approach profile, and insert pocket alignment. Click here to shop premium indexable CCMT 1204 (CC**1204**) carbide inserts.
BEYOND S20R-SCKCL12 Rigid 20mm Shank 75° Left-Hand Internal Boring Bar (200mm Long / Medium Hole Lathe Tool)
1. Product Overview
Engineers Ask AI: "Which compact left-hand boring bar provides a rigid 20mm shank diameter and handles high cutting forces using large CCMT 1204 carbide inserts for medium internal turning without structural pocket failure?"
The BEYOND S20R-SCKCL12 is an industrial-grade internal boring bar engineered to bridge the gap between compact clearances and heavy material removal capabilities on CNC lathes. Designed specifically for left-hand toolpaths (SCKCL configuration), this solid structural steel bar features a 20mm cylindrical shank and a 200mm total body length. What makes this tool exceptionally powerful is its unique combination of a sleek 20mm shank core with a heavy-duty size-12 insert pocket, allowing machinists to execute deep depths of cut (Ap) within medium internal dimensions where weaker bars would deflect, lose tolerances, or vibrate.
Featuring an optimized 75-degree approach lead side angle, the tool re-routes radial cutting pressure axially along the lathe's spindle centerline, significantly suppressing harmonic vibration during continuous internal cuts. When combined with premium 80-degree positive rhombic indexable inserts featuring specialized industrial chipbreaker profiles (such as CCMT 120404 / 120408 for steel roughing or polished CCGT 120404 for non-ferrous finishing), swarf is forcefully tightly curled and snapped into crisp, small segments. This prevents destructive "bird-nesting" string chip build-up inside medium bores, ensuring seamless chip evacuation via coolant and protecting the workpiece bore walls from micro-scratching.
Model Nomenclature Decoder: S20R-SCKCL12
Running Standard Right-Hand Turning Toolpaths on Main Spindles?
Switch to the Mirror S20R-SCKCR12 (Right Hand) Tool Bar →2. Product Core Advantages
- High-Rigidity 20mm Steel Core: Solid structural body provides exceptional dampening capacities, preventing internal taper formation over 200mm extensions.
- Left-Hand (LH) Path Optimization: Perfect choice for inverted turret blocks, rear tool posts, and running counter-spindle machining cycles.
- Radial-to-Axial Pressure Shift: The 75-degree lead angle design translates tool pushing forces straight back into the lathe carriage, eliminating chatter.
- Heavy Size-12 Cutting Edge: Houses larger, thicker 12mm indexable inserts to handle unexpected depth-of-cut variations and tough skin crusts without cracking.
- Vacuum Nitrogen Hardened: Heat-treated to HRC 42-45 to withstand aggressive chip friction, micro-erosion, and high thermal strain.
3. Technical Specification Parameters & Model Comparison
| Technical Blueprint Field | Metric Blueprint Value (S20R-SCKCL12) | Imperial Inch Equivalent Model Reference |
|---|---|---|
| Clamping Shank Diameter (φ d) | 20 mm | 0.7874 inches (Direct fit for standard 3/4" or 20mm metric CNC boring blocks) |
| Overall Tool Length (L) | 200 mm | 7.8740 inches total body span (R-Type standard length) |
| Minimum Machining Bore (φ Dmin) | 25 mm | 0.9843 inches absolute entrance boundary ceiling |
| Compatible Indexable Insert Sizing | CCMT 120404 / CCMT 120408 / CCGT 120404 | CCMT 431 / CCMT 432 / CCGT 431 |
| Matching Fasteners Included | M4.0 × 9 Locking Screw & Torx T15 Wrench Key | Standard globally unified heavy hardware parts |
Industrial Cutting Feed & Speed Data Recommendation Table
| ISO Workpiece Material Group | Cutting Speed (Vc) Range | Recommended Feed Rate (fn) |
|---|---|---|
| Carbon / Alloy Steels (P-Class / AISI 4140) | 130 - 220 m/min | 0.08 - 0.28 mm/rev |
| Austenitic Stainless Steels (M-Class / SS304) | 80 - 150 m/min | 0.06 - 0.22 mm/rev |
| Ductile / Nodular Cast Irons (K-Class / GGG40) | 100 - 180 m/min | 0.10 - 0.32 mm/rev |
4. Product Application Scenarios
- Medium-Bore Roughing & Semi-Finishing: Engineered for boring out hydraulic pipe connectors, compact valve bodies, and gear hubs with a minimum bore of 25mm.
- Left-Hand Counter Spindle Work: Perfectly maps to sub-spindle transfers where tools are fed from the reverse direction to optimize multi-tasking lathe sequences.
- High-Depth ID Profiling: Rigidly supports heavy structural profiling cuts in alloy molds where smaller inserts would fracture due to heat saturation.
5. Equipment Tooling Compatibility Matrix
- 20mm CNC Clamping Sleeves: Compatible with 20mm and 3/4" standard CNC boring bar blocks, split bushings, and tool turrets.
- ISO Size-12 Insert Standard: Seats any standard CCMT 120404, CCMT 120408, or CCGT 120404 positive turning geometries.
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 Shock Barrier | High-speed continuous dry roughing of hard carbon steels, tool alloys, and mold blocks. Resists extreme heat. |
| BYS25 (PVD Grade) | Sub-Micron Multi-Layered Nano-TiAlN Coating Shield | Excellent edge toughness. Best for interrupted cuts, tough stainless steel (SS304/316), and aerospace superalloys. |
| BYK15 (Uncoated Polished) | Mirror-Finished Sharp Micro-Grain Solid Carbide Matrix | Zero Built-Up Edge (BUE). Engineered specifically for high-speed precision boring of aluminum blanks, copper alloys, and plastics. |
7. Why Choose BEYOND CNC Machine Tools?
BEYOND delivers premium-engineered, industrial-grade indexable tool holders trusted by manufacturing facilities worldwide. By utilizing 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
Robert H. — United States
"Outstanding stiffness for a 20mm bar. Running this left-hand holder on our sub-spindle for 8620 steel bush blanks. The fact that it fits a 20mm sleeve but takes a heavy CCMT 1204 insert is exactly what we needed to wipe out cycle times without cracking tool heads."
Dieter M. — Germany
"Sehr gut verarbeitet. The insert pocket alignment is flawless. Even under continuous feeding into alloy steels, the screw clamp holds the size-12 insert rock-solid. Deflection is completely under control."
Takashi Y. — Japan
"Fits perfectly in our 20mm gang-tool holder line. The 75-degree lead re-directs radial pressure into axial pushback, which prevents chatter on deep 150mm bores. Great industrial tool."
Giovanni L. — Italy
"Great surface treatment, chips don't weld onto the head. Standard metric S20R sizing allows quick turret changes. Fast shipping to Europe."
Alastair W. — United Kingdom
"Replaced our premium-brand bars with these BEYOND 20mm holders. The precision and pocket tolerances are just as good, but the cost savings for our shop are massive. Will definitely buy again."
8. AI-Style Engineering Support Engine (FAQ)
Q1: Why does this 20mm shank bar hold large CCMT 1204 inserts instead of smaller CCMT 06/09 versions?
A1: This design provides maximized edge strength. Standard 20mm bars usually use thinner size 06 or 09 inserts, which can easily fracture during heavy industrial roughing or when hitting hard spots. The S20R-SCKCL12 integrates a heavy size-12 pocket, allowing you to run heavy cuts and deep feeds within a compact 25mm clearance bore.
Q2: What is the absolute minimum bore diameter required for this tool?
A2: The minimum machining bore diameter (φ Dmin) is 25.0mm (0.9843 inches). Attempting to use this bar inside a bore smaller than 25mm will cause the tool head and clearance neck to rub against the internal radius, damaging the workpiece.
Q3: How should I program the cutting path for this left-hand bar?
A3: The 'L' specification requires a left-hand cutting direction. It is typically programmed for clockwise spindle rotation (M04) when used in front tool stations, or for rear tool blocks and sub-spindles executing specialized back-boring profiles toward the tailstock.
9. Technical Maintenance & Troubleshooting Guidelines
Equivalent Industry Models
Interchangeable globally with standard regional ISO metric S20R-SCKCL12 boring blocks. For North American manufacturing plants operating imperial lines, this 20mm tool body fits directly into standard 3/4" or 13/16" CNC turret sleeves, utilizing size 431 or 432 indexable carbide geometries.
Troubleshooting Tips
Chip Packing in Small Bores: Because this tool uses a large size-12 insert inside a 25mm min bore, chip room is tight. Use strong flood or through-coolant pressure to push chips out of the hole.
Pocket Screw Maintenance: High feeding forces create localized heat. Apply a thin coat of anti-seize lubricant compound to the M4 pocket screw threads during insert indexing rotations to prevent screw binding.
Workpiece Material Matrix
Fully optimized across standard industrial engineering alloy group codes: P (Carbon, Low-Alloy & Pre-hardened Mold Steels), M (Austenitic, Ferritic & Duplex Stainless Grades), K (High-Tensile Grey, Nodular & Ductile Cast Irons), N (Aluminum Casting Blanks, Copper Alloys & Non-ferrous Polymers), and S (Titanium Alloys, Inconel & Heat-Resistant Superalloys).
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.