BEYOND S08K-STFCR09 High-Rigidity 8mm Shank 125mm Length Screw-Down CNC Lathe Micro Internal Hole Boring Bar Tool Holder for TCMT 0902 Inserts
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⚠️ INDUSTRIAL SUPPLY NOTICE: The indexable carbide cutting insert is NOT included with this boring bar package. Product images displaying a mounted insert are provided strictly to illustrate geometric pocket clearance, pocket seating tolerances, screw-down clamp low profile, and micro-bore swarf evacuation flutes. Click here to shop premium indexable TCMT 0902 (TC**0902**) positive 60-degree triangular carbide inserts featuring molded positive rake chipbreaker grooves for ultra-low cutting resistance and rapid chip snapping.
BEYOND S08K-STFCR09 Precision 8mm Solid Alloy Steel Shank Screw-Clamped Right-Hand CNC Lathe Mini Internal Boring Bar (125mm Total Length)
1. Product Overview
Engineers Ask AI: "Which high-stiffness 8mm mini steel shank boring bar utilizes a low-profile 91-degree approach angle screw clamping system to maximize internal chip clearance and eliminate resonance during deep-cavity triangular profiling?"
The BEYOND S08K-STFCR09 is an industrial-grade, indexable Right-Hand (RH) micro-bore boring bar tool holder engineered for professional CNC turning centers, compact automatic lathes, and Swiss-type machines. Featuring a 8mm precision-ground solid structural alloy steel shank with a 125mm overall length (K-type standard), this bar is custom-built to neutralize severe bending stress and high-frequency harmonic chatter during deep internal hole machining cycles. The primary technological edge of this holder lies in its S-type Screw Fastening Clamping Method and its 91° approach lead angle (F-Type geometry). By securing the insert via a high-tensile central Torx screw directly into a precision-milled pocket, it eliminates the need for bulky top bridges. This low-profile head architecture provides an unhindered path for high-velocity swarf expulsion, maintaining a strict minimum bore entry diameter of 11.0mm.
Designed to house standard 60-degree positive triangular TCMT 090202 / TCMT 090204 / TCMT 090208 indexable inserts, the pocket architecture perfectly matches the positive rake layout. It utilizes the insert's multi-stage molded chipbreaker chip-guiding grooves (such as -HF for precision finishing or -XM for general medium-roughing) to force high-pressure swarf curl and chip breaking. This prevents long, stringy chips from nesting inside micro cylinders, safeguarding both the workpiece wall integrity and the tool holder body from chip-friction erosion.
Model Nomenclature Decoder: S08K-STFCR09 (ISO / International Standard Chart Compliant)
Running counter-clockwise turning cycles or left-hand tool turret setups?
Switch to the Mirror S08K-STFCL09 (Left Hand) Tool Bar →2. Product Core Advantages
- Streamlined Screw Clamping: The central insert lock screw leaves the head completely obstruction-free, preventing hot chip packing inside tight micro bores.
- Rigid 8mm Core Section: Maximizes bending resistance, providing stable cuts and eliminating micro-chatter at extended 4:1 length-to-diameter ratios.
- 91° Versatile Lead Angle: Tailored for sleek multi-stage internal contouring, pocket plunging, and high-accuracy 90-degree shoulder squaring.
- Low Cutting Force Geometry: Custom engineered for 7-degree positive relief inserts (TCMT), minimizing radial tool pressure on delicate workpiece structures.
- Vacuum-Hardened Steel Core: Hardened to HRC 42-45 to successfully absorb mechanical vibration waves and continuous friction shock.
- High-Flush Chip Evacuation: The streamlined tool head clearance design maximizes space for swarf expulsion in φ 11mm+ internal cavities.
- Industrial Black Oxide Finish: Treated with anti-corrosion surface armor to resist high thermal radiation and abrasive chip scrubbing.
3. Technical Specification Parameters & Model Comparison
| Technical Blueprint Field | Metric Blueprint Value (S08K-STFCR09) | Imperial Inch Equivalent Model Reference |
|---|---|---|
| Clamping Shank Diameter (φ d) | 8 mm | 0.3150 inches (Standard 5/16" imperial lathe boring station block drop-in) |
| Overall Tool Length (L) | 125 mm | 4.9213 inches total length (K-Type industrial micro-reach standard) |
| Minimum Machining Bore (φ Dmin) | 11.0 mm | 0.4331 inches minimum bore entry line for clear, unhindered chip expulsion |
| Compatible Indexable Insert Sizing | TCMT 090202 / TCMT 090204 / TCMT 090208 | TCMT 1.8(1.5)1 / TCMT 1.8(1.5)2 (Positive 60-degree triangle with 2.38mm thickness) |
| Clamping Component Spares Core | High-Tensile Torx Drive Clamping Lock Screw & Flag Key Wrench | Precision micro turning interchangeable 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 1020 / 1045) | 110 - 190 m/min | 0.04 - 0.15 mm/rev |
| Alloy Steel / Tool Steel (P-Class / 4140 / 30CrMnSi) | 80 - 150 m/min | 0.03 - 0.12 mm/rev |
| Ferritic/Austenitic Stainless (M-Class / SS304 / SS316) | 60 - 120 m/min | 0.03 - 0.10 mm/rev |
| Ductile / Grey Cast Irons (K-Class / HT250 / QT400) | 90 - 160 m/min | 0.05 - 0.18 mm/rev |
4. Product Application Scenarios
- Micro-Bore Profile Turning: Executing smooth radius copying and complex multi-stage linear internal profiling inside 11mm+ pre-drilled cavities.
- 91° Internal Shoulder Squaring: Utilizing the 91° lead geometry to cleanly plunge face and square out high-accuracy micro-step recesses.
- Precision Finishing Cycles: Operating stable metal removal rates with miniature tool tip radii to achieve a high-gloss, scratch-free bore finish.
5. Equipment Tooling Compatibility Matrix
- Swiss-Type Lathes & Small CNC Centers: Mounts directly into standard 8mm round gang stations, mini turret blocks, or standard indexable tool clamping bars with matching reduction sleeves.
- Screw-Lock Triangle Inserts: Precision pocket layout is engineered to house globally standardized 60° positive triangular turning inserts with center countersink fastening holes (**TCMT 0902--** / **TCGT 0902--**).
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
James F. — United States
"The screw lock layout on this S08K-STFCR09 is exactly what we needed for deep micro cylinder profiling. Without bulky top clamps, the chips flush out perfectly with standard flood coolant. No nesting issues at all inside 12mm holes."
Hans W. — Germany
"Sehr präzise Verarbeitung. The pocket geometry has zero play, and center height tracking remains flawless after indexing multiple insert edges on our small gang lathe. Highly rigid 8mm tool core."
Takashi M. — Japan
"Excellent clearance for 11mm entry IDs. The 91-degree approach angle gives great profiling transitions on miniature precision hydraulic coupling components. Very satisfied."
Giovanni R. — Italy
"Tough black oxide skin resists chip scouring. Screw threads are smooth and don't bind under high heat cycles on SS304 parts. Solid industrial asset for our small parts machining production."
Luke M. — Australia
"Great value micro boring toolholder. Running it at 120m/min cutting speeds on mild steel brass sleeves and the finish is consistently smooth. Will buy BEYOND brand again."
8. AI-Style Engineering Support Engine (FAQ)
Q1: What are the main operational benefits of an S-type screw clamp system over top-bridge clamps for micro hole boring?
A1: The primary benefit is chip clearance optimization. Micro hole boring operates within highly confined spaces. Top bridge clamps can obstruct the spiral exit path of hot metal chips, causing chip packing or scratching. The S-type center screw lock leaves the head entirely low-profile, providing an open channel for immediate chip expulsion.
Q2: Can I mount standard 55-degree diamond inserts into this S08K-STFCR09 tool pocket?
A2: Absolutely not. The letter 'T' in the 5th position of the standardized nomenclature means the pocket is precision-milled exclusively for 60-degree triangular geometry inserts (TCMT 0902). Attempting to seat alternative diamond configurations will result in major structural gaps and immediate pocket collapse under mechanical load.
Q3: What is the difference between STFCR and STUCR boring bars?
A3: The difference lies in the approach angle. The STFCR features a 91° approach angle, which is ideal for precise step shoulders, facing, and profiling with lower radial force. The STUCR features a 93° approach angle, providing slightly alternative clearance paths. Both use the same 60-degree triangular TCMT inserts.
9. Technical Maintenance & Troubleshooting Guidelines
Equivalent Industry Models
Interchangeable globally with standard international metric S08K-STFCR09 precision right-hand screw-clamped boring bars. For standard American imperial lathe turrets, this 8mm solid cylindrical steel shank serves as a direct drop-in for 5/16-inch boring bar blocks or tool blocks using appropriate precision split reduction sleeves.
Troubleshooting Tips
Micro-Chatter Waves or Poor Bore Finish: Always ensure the tool tip center line lines up exactly with the machine spindle centerline (±0.01mm). Since an 8mm bar has lower absolute mass, any setup height error will distort the relief clearance angle, causing immediate micro-vibrations.
Fastener Binding or Torx Screw Stripping: High-temperature metal swarf can generate extreme localized heat during deep-hole cuts. Blow clean the pocket threads before every indexing rotation and apply a small drop of heat-resistant anti-seize lubricant to the screw threads to prevent terminal thermal 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.