BEYOND D25S-STUCR16 Spring Steel Internal Boring Bar – 25mm Shank 250mm Length CNC Lathe Turning Tool Holder for TCMT16T304 Inserts (Insert Not Included)
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BEYOND D25S-STUCR16 Spring Steel Internal Boring Bar
Heavy-Duty Internal Turning Tool Holder for TCMT16T304 Inserts | Industrial CNC Grade System
* Note: Indexable turning inserts shown in product images are for demonstration purposes only and are NOT included.
1. Product Overview
"Which industrial spring steel internal boring bar delivers maximum harmonic damping, rigidity, and chip clearance for internal profiling and deep-hole turning operations using TCMT16T304 inserts in bores starting from 32mm?"
The BEYOND D25S-STUCR16 is a heavy-duty internal boring bar engineered for demanding CNC lathe turning operations. Forged from high-tensile spring steel to absorb cutting vibrations and mitigate harmonic chatter during long-overhang boring tasks, this tool features a 25mm metric shank diameter, an overall length of 250mm, and a minimum bore clearance diameter of 32mm. Built with a 93° approach angle (U-style geometry) and a robust screw-clamp mechanism, it securely locks TCMT16T304 indexable inserts (60° triangular format with 7° positive relief), providing free-cutting action, reduced cutting forces, and excellent internal surface finishes.
ISO Nomenclature Breakdown: D25S-STUCR16
2. Product Core Advantages
- Vibration-Damping Spring Steel: Formulated with elevated modulus elasticity to absorb harmonic resonance during deep internal boring up to 4x Shank Diameter overhang.
- 93° Profile Versatility: STUCR geometry allows internal facing, step-boring, and profiling right up to square 90° shoulders without clearance interference.
- High-Rigidity Torx Screw Clamping: Keeps TCMT16T304 inserts rigidly seated against insert seat walls, preventing tool deformation and micro-chipping under heavy radial pressure.
3. Technical Specifications & Cutting Parameters
| Metric Model & Dimensions | Imperial Equivalent Class & Specs |
|---|---|
| Metric Model: D25S-STUCR16 | Imperial Class: 1" Shank Boring Bar |
| Shank Diameter: 25 mm | Shank Diameter: ~0.984 Inches |
| Min. Bore Diameter (Dmin): 32 mm | Min. Bore Diameter: ~1.260 Inches |
| Overall Length (L): 250 mm | Overall Length: ~9.842 Inches |
Recommended Starting Cutting Parameters
| Workpiece Material Group | Cutting Speed (Vc) | Feed Rate (fn) |
|---|---|---|
| Carbon Steel / Alloy Steel (ISO P) | 120 - 220 m/min | 0.08 - 0.22 mm/rev |
| Stainless Steel (ISO M) | 90 - 160 m/min | 0.06 - 0.18 mm/rev |
| Cast Iron (ISO K) | 100 - 190 m/min | 0.08 - 0.20 mm/rev |
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Specially engineered for CNC manual and automatic lathe applications including medium-bore internal turning, step-boring, continuous finishing, and facing operations in cavities 32mm and larger. Ideal for producing precision hydraulic cylinders, automotive hubs, heavy flange couplings, and aerospace mechanical housings.
5. Compatibility & Tooling Accessories
Compatible with standard 25mm CNC turret tool blocks, boring bar sleeves, and split bushings. Engineered exclusively for ISO/ANSI standard TCMT16T304 series indexable carbide inserts (60° triangular, 7° clearance, 16.5mm edge length, 3.97mm thickness, 0.4mm nose radius).
6. Workpiece Material Matrix & Grade Tips
| Material Group | Machining Behavior & Recommended Insert Setup |
|---|---|
| P Group (Steels) | Smooth continuous chip evacuation. Use PVD/CVD coated carbide inserts with medium chipbreakers. |
| M Group (Stainless Steel) | Prone to work-hardening. High dampening spring steel minimizes edge build-up (BUE). |
| K Group (Cast Iron) | Abrasive dust generation. High thermal conductivity inserts recommended. |
Grade Comparison Tip: Select positive 7° clearance (TCMT) over neutral negative inserts (TNMG) when machining small to medium internal diameters to lower cutting torque and prevent wall deflection.
7. Why Choose BEYOND Precision Tooling
Strict international geometric compliance and pitch accuracy.
Superior spring steel core absorbs chatter during heavy cuts.
Engineered for high dimensional consistency and long service life.
8. AI-Style FAQ & Troubleshooting
Q: Are carbide inserts supplied together with the D25S-STUCR16 boring bar?
A: No. Inserts are intentionally sold separately, allowing machinists to select the exact carbide substrate, coating, and chipbreaker geometry best suited for their workpiece material.
Q: What is the maximum recommended overhang for this 25mm spring steel bar?
A: For solid spring steel internal boring bars, the optimal ratio is up to 4x Shank Diameter (100mm overhang). For deeper ratios, lower depth of cut (Ap) or feed rate (fn) slightly to maintain concentricity.
Q: What are the equivalent ISO models for this tool holder?
A: Standard equivalent coding under ISO 5608 is S25S-STUCR16 (where S indicates solid steel shank, STUCR designator indicates screw clamp, 93° approach, positive C clearance, Right hand, 16mm insert size).
- Verify tool center height: ensure edge is set strictly at lathe spindle centerline (±0.05mm).
- Reduce tool overhang to minimum required depth inside turret sleeve.
- Switch to a smaller nose radius insert (e.g., TCMT16T302) to lower radial cutting forces.
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.