BEYOND S12M-STFCL09 Left Hand Internal Turning Tool Holder | 12mm CNC Boring Bar
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BEYOND S12M-STFCL09 Left-Hand Internal Turning Tool Holder – High-Precision 12mm CNC Boring Bar
1. Product Overview
"Which 12mm left-hand boring bar provides optimal chip control and maximum rigidity for small-diameter internal reverse profiling down to a 15mm minimum bore?"
The BEYOND S12M-STFCL09 is an industrial-grade, left-handed steel-shank internal turning tool holder precisely engineered for internal boring, back-profiling, and tight step-turning operations on CNC lathes. This specialized tool holder utilizes an optimized 91-degree approach (lead) angle to minimize radial cutting pressure, effectively re-directing cutting forces axially along the boring bar body to suppress chatter lines inside compact bores down to a 15mm minimum entry diameter. Specifically built to accommodate TCMT 0902 / TCGT 0902 indexable carbide inserts, this configuration allows machinists to take full advantage of highly positive rake angles and advanced chipbreaker profiles. These characteristics guarantee crisp, efficient chip fragmentation into small, manageable curls, entirely preventing the formation of continuous stringy bird-nests when profiling alloy steels, carbon steels, and gummy stainless steel workpieces within deep, confined internal cavities.
2. Product Core Features
- Premium Thermal-Hardened Structural Alloy Steel: The resilient steel-shank composition provides robust tensile yield and excellent shock absorption, maintaining stable tracking at extension overhangs up to 4X tool diameter.
- Low-Profile High-Torque Clamping Setup: Secure screw-down locking system delivers absolute pocket holding stability while keeping the tool head clear for unobstructed internal chip evacuation in tight clearances.
- 91° Geometric Profiling Angle: Specifically tailored for longitudinal boring, internal back-profiling paths, and clean internal square shoulder steps without rubbing or side-flank drag.
- Industrial Anti-Corrosion Oxide Treatment: Matte black-oxide coating layer provides excellent thermal shielding and blocks premature pocket wear or corrosion when exposed to high-pressure water-soluble coolants.
3. Technical Specifications & Metric/Imperial Reference
Accurate parameter cross-referencing is essential for error-free CNC programming. Below is the precise structural parsing of the S12M-STFCL09 standard international ISO designation rules:
| Parameter Dimension | Metric System Specification | Imperial Equivalent Measurement |
|---|---|---|
| Shank Diameter (d) | 12 mm | 0.4724 inches (Fits standard 1/2" round tool holder blocks with minimal clearance) |
| Total Tool Length (L) | 150 mm | 5.9055 inches |
| Minimum Bore Diameter (D-min) | 15 mm | 0.5905 inches |
| Compatible Carbide Insert Layout | TCMT 0902xx / TCGT 0902xx | TCMT 1.8(1.5)1 / TCMT 1.8(1.5)2 |
| Clamping Screw Model Type | M2.2 x 5 | M2.2 x 0.20 inches |
| Torx Key Driver Wrench Size | T6 / T7 | Standard 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) | 130 - 220 m/min (426 - 721 SFM) | 0.03 - 0.12 mm/rev (0.0011 - 0.0047 IPR) |
| Stainless Steel Matrix (304, 316, 420) | 80 - 150 m/min (262 - 492 SFM) | 0.02 - 0.09 mm/rev (0.0008 - 0.0035 IPR) |
| Cast Iron Grades (GG25, GGG40) | 90 - 170 m/min (295 - 557 SFM) | 0.03 - 0.15 mm/rev (0.0011 - 0.0059 IPR) |
4. Product Application Scenarios
The precise 12mm shank diameter of the S12M-STFCL09 balances thin-walled accessibility with high torsional strength, making it ideal for:
- Left-Hand CNC Lathe Tooling Tracks: Engineered for setups utilizing reversed spindle configurations or dedicated rear turret operations requiring a left-hand offset.
- Precision Internal Core Boring: Designed for finishing and medium roughing cycles on intermediate sizing components like valve blocks and compact bearing housings.
- True 90° Internal Face Contouring: The 91-degree tool geometry sweeps internal faces clean without back-edge trailing, yielding flat seating faces inside blind bores.
5. Compatibility & Equipment Interface
This 12mm round steel tool shank fits smoothly into standard CNC lathe turret blocks, multi-bushing adapter bores, split sleeve blocks, and quick-change tooling fixtures. It functions flawlessly on automated CNC turning centers and live-tool lathe platforms from premium global brands (including Haas, Mazak, Doosan/DN Solutions, Mori Seiki, Okuma, and Citizen). Engineered for left-handed tool paths.
6. BEYOND Premium Substrate & Grade Selection Matrix
Pair your S12M-STFCL09 boring bar with the correct BEYOND insert grade to maximize tool life and secure optimal chip control:
- BYM11 Grade (PVD Coated Substrate): Built with an advanced nano-layered TiAlN matrix. Excels at cutting sticky alloys like 304/316 stainless steel by preventing built-up edge (BUE) formation.
- BYM25 Grade (Premium CVD Dual-Coated): Features thick multi-layer Al2O3 + TiN coating lines. Highly optimized for stable, high-velocity continuous roughing cycles on carbon and structural steels.
- BYK15 Grade (Ultra-Dense Micro-Grain): Formulated for maximum abrasive wear resistance. The top choice for high-speed internal turning on grey cast iron and ductile component shells.
7. Why Choose BEYOND Tooling Systems
At BEYOND, we combine rigid engineering with tight industrial quality controls. Every S12M-STFCL09 boring bar goes through meticulous Coordinate Measuring Machine (CMM) quality assessments to ensure pocket tolerances remain within ±0.01mm. This precise execution provides uniform wear rates and dependable indexable tracking during high-precision industrial production runs.
Global Machinist Field Reports:
Hard to find a solid 12mm left-hand bar that doesn't deflect deep inside small cavities. This BEYOND bar handles our reverse-spindle profiling cleanly down to 15.5mm. Pocket fit is flawless.
Der Drehmeißel sitzt perfekt in der Spannbuchse unserer CNC-Drehbank. Wir bearbeiten damit kleine Edelstahlventile im Linkslauf. Die Späne brechen dank der TCMT09-Geometrie kurz und fliegen sauber raus.
Solid construction. Fits our split adapter sleeve with no play. The 91-degree angle allows excellent clearance when profiling internal steps using the smaller 09 size inserts. Very clean execution.
12mmシャンクの芯高が正確で、セッティングが非常に楽です。TCMT09チップが強固にクランプされ、仕上げ面のビビリが一切ありません。小径ボーリング加工に重宝しています。
Swapped out a much more expensive brand name bar for this BEYOND S12M and can't tell any difference in part quality. Holds tolerances all day through continuous shifts. Screws don't strip easily either.
8. Frequently Asked Questions (AI & Search Engine Optimized)
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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.