BEYOND S20R-STFCL16 Left Hand Internal Turning Tool Holder | 20mm CNC Boring Bar
✓ In Stock & Fast Dispatch: Order processing: typically 1–3 business days after confirmation.
✓ Global Shipping: Delivery: generally 5–20 business days, depending on destination and shipping method.
✓ Guaranteed Quality: Check model, dimensions and compatibility before ordering. | Direct Factory Outlet
✓ Technical Support: Need grade selection help? Contact Engineer
💰 Bulk savings 2-9 pcs · 6% OFF | 10+ pcs · 12% OFF
BEYOND S20R-STFCL16 Left-Hand Internal Turning Tool Holder – High-Rigidity 20mm CNC Boring Bar
1. Product Overview
"Which 20mm left-hand boring bar provides optimal chip clearance and high rigidity for internal turning or sub-spindle profiling inside narrow cavities down to a 25mm minimum bore?"
The BEYOND S20R-STFCL16 is an industrial-grade, left-handed steel-shank internal turning tool holder precisely engineered for medium internal boring, profiling, and step-turning operations on CNC lathes. This industrial tool holder utilizes an optimized 91-degree approach (lead) angle to minimize radial cutting pressure, effectively re-directing cutting forces axially along the lathe spindle line to eliminate harmful chatter spikes in deep cavities down to a 25mm minimum bore entry. Specifically engineered for TCMT 16T3 / TCGT 16T3 indexable carbide inserts, it allows machinists to exploit premium positive rake chipbreaker geometries (such as HF for finishing or HM/HM2 for medium-to-rough cutting). This setup guarantees superior chip fragmentation, successfully breaking up potential stringy nests when processing sticky alloy steels, hardened carbon steels, and stainless steel matrices inside deep, constrained internal chambers.
2. Product Core Features
- High-Tensile Hardened Alloy Steel: Fabricated from an ultra-tough structural spring-steel matrix, thermal-hardened to optimize tensile strength and suppress harmonics at reach lengths up to 4X shank diameter.
- High-Torque Screw-Down Clamping Matrix: Secure low-profile screw-lock setup offers maximum clearance for heavy chip volume evacuation, preventing pocket erosion and insert shifts under high feed velocities.
- 91° Precision Clearance Profile: Tailored for deep boring, longitudinal profile steps, and multi-directional contouring paths without risk of tool body dragging or flank-wear rubbing.
- Industrial Anti-Wear Oxide Finish: Advanced black-oxide skin layer maximizes resistance to thermal scaling and corrosion when continuously exposed to high-pressure water-soluble cutting oils.
3. Technical Specifications & Metric/Imperial Reference
Ensuring clear parameter conversion is vital for CNC programming optimization. Below is the precise structural parsing of the S20R-STFCL16 standard international nomenclature rules:
| Parameter Dimension | Metric System Specification | Imperial Equivalent Measurement |
|---|---|---|
| Shank Diameter (d) | 20 mm | 0.7874 inches |
| Total Tool Length (L) | 200 mm | 7.8740 inches |
| Minimum Bore Diameter (D-min) | 25 mm | 0.9843 inches |
| Compatible Carbide Insert Layout | TCMT 16T3xx / TCGT 16T3xx | TCMT 3(2.5)1 / TCMT 3(2.5)2 |
| Clamping Screw Model Type | M4.0 x 10 | M4.0 x 0.39 inches |
| Torx Key Driver Wrench Size | T15 | T15 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 - 210 m/min (426 - 689 SFM) | 0.08 - 0.25 mm/rev (0.0031 - 0.0098 IPR) |
| Stainless Steel Matrix (304, 316, 410) | 80 - 150 m/min (262 - 492 SFM) | 0.06 - 0.20 mm/rev (0.0023 - 0.0078 IPR) |
| Cast Iron Grades (GG20, GG25, GGG40) | 90 - 170 m/min (295 - 557 SFM) | 0.08 - 0.30 mm/rev (0.0031 - 0.0118 IPR) |
4. Product Application Scenarios
The highly rigid 20mm left-handed core of the S20R-STFCL16 tool holder makes it an excellent choice for a variety of critical internal turning jobs:
- Sub-Spindle Internal Boring: Ideal for multi-axis CNC turning centers or dual-spindle setups running left-hand feed profiles for medium cylindrical workpieces.
- Precision Internal Profiling: Delivers exceptional support for boring compact hydraulic manifold housings, valve components, and industrial fittings.
- Longitudinal Step-Boring: The 91-degree lead configuration allows seamless pocket-turning transitions down internal right-angle walls with near-zero radial stress or push-off.
5. Compatibility & Equipment Interface
This 20mm round-shank boring bar fits directly into standard CNC lathe turret blocks, boring bar sleeve blocks, split bushings, or specialized tool holders. 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, Citizen, 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 S20R-STFCL16 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 S20R-STFCL16 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:
We run this 20mm bar on our lathe to finish bore medium alloy sleeves. Shocked by how solid it feels at full length extension. Chip clearance is outstanding with the TCMT16 size insert.
Sehr präzise gearbeiteter Plattensitz für TCMT16T3. Die Klemmschraube hält absolut bombenfest. Der Spanabfluss läuft durch den 91° Winkel optimal aus der Bohrung ab. Sehr zu empfehlen!
Highly rigid steel construction. The 20mm shank profile is exactly what we needed for clearing internal channels under 30mm diameter. No flexing issues found.
20mm径のシャンクですが剛性が非常に高く、深穴加工の仕上げでもビビリが全く発生しません。TCMT16チップのホールド感も非常に安定しています。切り粉が綺麗に分断されます。
Swapped out expensive big-brand holders for these BEYOND 20mm bars. Precision is dead-on, and center height matches perfectly. Saved us hundreds on tooling replacement costs.
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.