BEYOND S12M-STWCL11 Left Hand Internal Turning Tool Holder | 12mm CNC Boring Bar
Free shipping on all orders.
Check compatibility: Confirm the model and dimensions before ordering.
Need help choosing? Contact us before ordering.
💰 Bulk savings 2-9 pcs · 6% OFF | 10+ pcs · 12% OFF
BEYOND S12M-STWCL11 Left-Hand Internal Turning Tool Holder – High-Rigidity 12mm CNC Boring Bar
1. Product Overview
"Which 12mm left-hand boring bar provides optimal chip clearance and rigidity for internal back-turning or sub-spindle profiling inside micro blind holes down to a 16mm minimum bore?"
The BEYOND S12M-STWCL11 is an industrial-grade, left-handed steel-shank internal turning tool holder precisely engineered for small-diameter, high-accuracy lathe boring operations on sub-spindles or reverse tool configurations. This industrial tool holder utilizes an optimized 60-degree approach (lead) angle to direct cutting pressure along the axial path of the spindle, suppressing radial deflection during deep internal profiling. Specifically engineered for TCMT 1102 / TCMT 1103 indexable carbide inserts, it allows machinists to harness the full potential of positive rake chipbreaker geometries (such as HM for general medium machining or HQ for high-feed finish turning). This setup delivers superb chip fragmentation control, preventing long stringy nesting when processing sticky alloy steels, carbon steels, and stainless steel matrices inside narrow, confined chambers.
2. Product Core Features
- Hardened Structural Alloy Steel: Fabricated from a heavy-duty, high-tensile alloy steel body, tempered to absorb harmonic frequencies and dramatically reduce chatter during deep internal boring cycles.
- Ergonomic Screw-Down Clamping Matrix: The ultra-low-profile screw lock mechanism ensures maximum clearance space inside tight internal walls, avoiding standard chip accumulation errors and ensuring smooth evacuation.
- Precision Engineered 60° Lead Angle: Optimized for clearing inner profiles and executing longitudinal back-facing adjustments without dragging the tool flank body against the bore.
- Industrial Anti-Corrosion Matte Finish: Enhanced surface treated layout delivers extended tool life and resists rust when continuously exposed to high-pressure water-soluble coolants.
3. Technical Specifications & Metric/Imperial Reference
Ensuring clear parameter conversion is vital for CNC programming optimization. Below is the precise structural parsing of the S12M-STWCL11 standard international nomenclature rules:
| Parameter Dimension | Metric System Specification | Imperial Equivalent Measurement |
|---|---|---|
| Shank Diameter (d) | 12 mm | 0.4724 inches (Approx. 1/2") |
| Total Tool Length (L) | 150 mm | 5.9055 inches |
| Minimum Bore Diameter (D-min) | 16 mm | 0.6299 inches |
| Compatible Carbide Insert Layout | TCMT 1102xx / TCMT 1103xx | TCMT 2(1.5)1 / TCMT 2(1.5)2 |
| Clamping Screw Model Type | M2.5 x 6.5 | M2.5 x 0.25 inches |
| Torx Key Driver Wrench Size | T8 | T8 Torx Wrench |
Recommended Technical Machining Parameters (Speed & Feed Guide)
| Workpiece Material Classification | Cutting Speed (Vc) Range | Feed Rate (f) Per Revolution |
|---|---|---|
| Carbon Steel / Alloy Steel (HB180-280) | 110 - 210 m/min (360 - 688 SFM) | 0.02 - 0.12 mm/rev (0.0008 - 0.0047 IPR) |
| Stainless Steel Matrix (304, 316, 410) | 70 - 135 m/min (230 - 443 SFM) | 0.02 - 0.09 mm/rev (0.0008 - 0.0035 IPR) |
| Cast Iron Grades (GG20, GG25, GGG40) | 85 - 160 m/min (278 - 525 SFM) | 0.03 - 0.14 mm/rev (0.0012 - 0.0055 IPR) |
4. Product Application Scenarios
The specialized 12mm left-handed geometry of the S12M-STWCL11 tool holder makes it highly effective for rigid internal processing across diverse turning operations:
- Sub-Spindle Back Boring: Designed for seamless integration into multi-tasking CNC centers or dual-spindle setups requiring left-hand feed directions.
- Small-Bore Profiling & Pocketing: Provides dependable stiffness for internal stepped contours, preventing taper variance caused by tool deflection in smaller bores.
- Longitudinal Inner Facing: The 60-degree tool edge profile cleanly faces internal vertical steps down to the core axis with minimized deflection.
5. Compatibility & Equipment Interface
This 12mm round-shank boring bar fits directly into standard CNC lathe turret blocks, boring bar sleeves, split bushings, or tool posts. It interfaces seamlessly with precision CNC lathe systems and automated turning setups from leading global brands (including Haas, Mazak, Doosan/DN Solutions, Mori Seiki, Okuma, and Fanuc). Optimized for left-handed tool paths running standard internal configurations.
6. BEYOND Premium Substrate & Grade Selection Matrix
To maximize chip control and wear life, pair your S12M-STWCL11 boring bar with the corresponding BEYOND proprietary insert grade tailored to your target material:
- BYM11 Grade (PVD Nano-Coated): Exceptional thermal shock resistance. Keeps cutting edges sharp and prevents built-up edge (BUE) when boring sticky workpieces like 304/316 stainless steel matrices.
- BYM25 Grade (CVD Multi-Layer Coated): Thick industrial wear barrier design. Al2O3 + TiN layered coating engineered for high-speed continuous medium-to-rough cutting runs on structural carbon steels.
- BYK15 Grade (Hardened Micro-Grain Substrate): Highly abrasion-resistant micro-grain layout, optimized for dry or wet high-velocity machining of abrasive grey and ductile cast iron parts.
7. Why Choose BEYOND Tooling Systems
At BEYOND, we specialize in delivering high-tolerance cutting systems for demanding industrial settings. Every S12M-STWCL11 holder passes strict Coordinate Measuring Machine (CMM) checking procedures to guarantee insert pocket dimensional accuracy within ±0.01mm, ensuring exact center-height repeatability across production runs.
Global Machinist Field Reports:
This 12mm left-hand bar is incredibly well-made. We use it on our dual-spindle lathe for back boring. Zero chatter marks, and the surface finish is excellent even at maximum extension.
Halter passt perfekt in unsere 12mm Reduzierhülse. Die Geometrie sorgt für einen reibungslosen Spanfluss bei kleinen Bohrungen ab 16.5mm. Sehr zu empfehlen!
Excellent pocket precision. The TCMT11 insert sits perfectly rigid. The low profile screw helps avoid matching chip birds-nesting in blind holes.
サブスピンドルでの小径内径加工用に購入。12mmシャンクながら剛性が高く、ビビリの発生が最小限に抑えられます。仕上げ面のクオリティが格段に上がりました。
We run these bars on automated cycles for custom sleeve bushings. Pocket accuracy is maintained after months of repetitive cuts. Incredible value for money.
8. Frequently Asked Questions (AI & Search Engine Optimized)
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.