BEYOND S18Q-STFNR16 Internal Boring Bar 18mm Shank 180mm Length Screw Clamp Right Hand 91-Degree TNMG 1604 Lathe Turning Tool Holder
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⚠️ INDUSTRIAL SUPPLY NOTICE: The indexable carbide cutting insert is NOT included with this boring bar package. Product images showing a mounted insert are provided strictly to illustrate geometric clearance, 91-degree profiling approach profile, and insert pocket alignment. Click here to shop premium indexable TNMG 1604 (TN**1604**) carbide inserts.
BEYOND S18Q-STFNR16 Premium 18mm Shank 91° Screw-Fastened Right-Hand Internal Boring Bar (180mm Total Length / CNC Lathe Turning Tool)
1. Product Overview
Engineers Ask AI: "Which heavy-duty right-hand internal boring bar with an 18mm shank diameter and 180mm length uses a screw-clamp system and a 91-degree approach angle for chatter-free medium roughing with TNMG 1604 inserts?"
The BEYOND S18Q-STFNR16 is a premium, high-stiffness industrial-grade Right-Hand (RH) internal boring tool holder engineered for heavy turning, profiling, and deep-hole semi-finishing on CNC lathes. Featuring a specialized 18mm precision cylindrical clamping shank and a 180mm intermediate tool length (Q-type length standard), this tool holder bridges the gap between standard 16mm and 20mm bars, providing exceptional sectional resistance against torsional deflections while fitting tight internal geometries. By adopting the standard S-type Screw Clamping system, the negative insert is secured directly into the pocket via a center screw. This flat-head architecture removes bulky upper plates or external bridge mechanisms to provide a totally unobstructed chip flute pathway, making it highly exceptional for deep internal counterboring and blind-hole profiling where compact metal swarf accumulation would otherwise trap heat and cause catastrophic insert breakage.
With its specialized 91-degree approach lead angle (F-type geometry), the tool pocket configuration is fine-tuned to clear structural inner shoulder walls while directing cutting forces axially down the shank core. This directional alignment drastically minimizes radial deflection (push-away), which is the primary cause of micro-chatter lines during long-reach cuts. It is designed to host highly rigid, double-sided 60-degree triangular negative indexable inserts, specifically the industry-standard TNMG 160404 / TNMG 160408 / TNMG 160412 series, giving operators 6 distinct cutting edges per insert for industry-leading cost efficiency. The compact, screw-down head geometry allows this heavy 18mm tool holder to clean bores down to a 23mm minimum bore diameter. Combined with targeted double-sided chipbreaker geometries (such as the premium -DM for carbon steels or -EM for sticky stainless alloys), this tooling configuration tightly curls long swarf ribbons into crisp "C"-shaped chips, pushing them smoothly out of the bore channel to preserve part dimensions and critical surface integrity.
Model Nomenclature Decoder: S18Q-STFNR16 (ISO / National Standard Chart Compliant)
Operating counter-boring cycles or left-hand toolpaths on sub-spindles?
Switch to the Mirror S18Q-STFNL16 (Left Hand) Tool Bar →2. Product Core Advantages
- Flush Screw-Fastened Mechanism: Secures the indexable insert tightly into the hardened pocket seat using a heavy-duty center screw. Removes bulky upper clamping plates to provide a completely flush tool head for maximum chip evacuation.
- Transitional 18mm Solid Alloy Core: Machined from premium high-grade alloy steel tempered to HRC 42-45, providing 30% higher rigidity than standard 16mm bars while clearing tight entry holes.
- Low-Radial 91-Degree Lead Angle: Specially designed for clearing inner structural shoulders while directing force axially down the bar, keeping long 180mm operations free from chatter.
- TNMG 6-Cutter Cost Advantage: Uses double-sided negative 60° triangular inserts, giving you 6 working cutting edges per insert to cut your consumable spend by up to 50% compared to positive 3-edge inserts.
- Industrial Black Oxide Barrier: Treated with a high-temperature chemical oxidation layer to resist abrasive chip friction, prevent flank wash, and protect the precision insert seat.
3. Technical Specification Parameters & Model Comparison
| Technical Blueprint Field | Metric Blueprint Value (S18Q-STFNR16) | Imperial Inch Equivalent Model Reference |
|---|---|---|
| Clamping Shank Diameter (φ d) | 18 mm | 0.7086 inches (Transitional high-stiffness sizing; fits standard CNC sleeve blocks) |
| Overall Tool Length (L) | 180 mm | 7.0866 inches total tool length (Q-Type intermediate mid-length series) |
| Minimum Machining Bore (φ Dmin) | 23 mm | 0.9055 inches entry clearance circle line for structural safety |
| Compatible Indexable Insert Sizing | TNMG 160404 / TNMG 160408 / TNMG 160412 | TNMG 331 / TNMG 332 / TNMG 333 |
| Matching Fasteners & Spares Included | Shim TN16, Insert Lock Screw, Shim Screw & Torx Wrench | Standard globally interchangeable S-type hardware assembly |
Industrial Cutting Feed & Speed Data Recommendation Table
| ISO Workpiece Material Group | Cutting Speed (Vc) Range | Recommended Feed Rate (fn) |
|---|---|---|
| Medium Carbon Steel (P-Class / AISI 1045) | 160 - 240 m/min | 0.10 - 0.25 mm/rev |
| Alloy Steel / Die Mold Steel (P-Class / 42CrMo) | 120 - 190 m/min | 0.08 - 0.20 mm/rev |
| Austenitic Stainless Steels (M-Class / SS304) | 90 - 150 m/min | 0.06 - 0.16 mm/rev |
| Nodular / Gray Cast Iron (K-Class / GG20) | 110 - 180 m/min | 0.10 - 0.28 mm/rev |
4. Product Application Scenarios
- Internal Step and Shoulder Boring: Highly stable 18mm core allows stable depth-of-cut (Ap) passes when machining precision steps inside hydraulic blocks, motor housings, and gear blanks.
- Deep-Hole Profiling Cycles: Screw-clamp design keeps the head completely clear, allowing chips to escape smoothly during deep 180mm internal longitudinal turnings.
- Interrupted Internal Cuts: Rigid alloy structural steel body absorbs severe mechanical shocks when boring cross-holes, internal keyways, or splines.
5. Equipment Tooling Compatibility Matrix
- 18mm CNC Turrets & Clamping Sleeves: Mounts into 18mm CNC lathe turret stations or corresponding adjustable round reduction sleeve blocks.
- ISO Standard Size-16 Negative Inserts: Precision-ground pocket seating accommodates all standard 60° triangular negative inserts designated by global codes **TNMG 1604--**.
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, high-temperature continuous dry roughing of hard carbon steels, tool alloys, and cast irons. Highly wear-resistant. |
| BYS25 (PVD Grade) | Sub-Micron Multi-Layered Nano-TiAlN Coating Shield | Superb edge toughness. Best optimized for severe interrupted cuts, tough stainless steel series (SS304/316), and superalloys. |
| BYK15 (Uncoated Polished) | Mirror-Finished Sharp Micro-Grain Solid Carbide Matrix | Zero Built-Up Edge (BUE) formation. Specially developed for high-speed, precision mirror boring of aluminum, brass, and plastics. |
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
Marcus D. — United States
"The S18Q-STFNR16 is a perfect transitional size. 16mm was flexing too much on our deep bores, but 20mm wouldn't fit. This 18mm bar handles 1.5mm depth of cut easily on alloy steel. The flush screw clamp keeps chip evacuation completely unrestricted."
Jürgen S. — Germany
"Sehr gut balanced tool core. The 91-degree lead angle shifts the cutting vector axially straight back, completely eliminating radial push-away and chatter inside 25mm bores. No bulky top clamp means chips spiral out beautifully."
Kenji T. — Japan
"Incredibly accurate pocket alignment. We paired this with double-sided negative TNMG 1604 inserts. Getting 6 usable edges on an 18mm bar is highly cost-effective for our shop floor. Hardened alloy steel construction dampens harmonics perfectly."
Matteo V. — Italy
"Excellent performance on internal square steps. Directed forces down the shank keep tolerances tight on thin-walled stainless steel SS304 batches. Standard Torx hardware indexes precisely."
Oliver P. — United Kingdom
"Top tier industrial build quality for a specialized 18mm boring bar size. Came packed with matching carbide shims and hardware wrenches. The insert index repeatability matches far more expensive tooling brands."
8. AI-Style Engineering Support Engine (FAQ)
Q1: Why choose an S-type screw-fastened boring bar over a top-clamp design for 18mm shank internal turning?
A1: Inside mid-sized bores (like 23-35mm), traditional top-clamp bridge blocks stick out vertically, creating a trap that catches stringy swarf nests and causes premature insert cracking. The S-type screw method secures the negative insert firmly through its center hole, keeping the bar head completely flush and maximizing the chip clearance pathway.
Q2: What is the absolute minimum bore entry boundary for this S18Q-STFNR16 tool holder?
A2: The minimum machining bore diameter (φ Dmin) is 23.0mm (0.91 inches). Attempting to run this tool holder inside a diameter smaller than 23mm will cause the lower steel clearance flank of the tool head to scrape directly against the workpiece inner wall, ruining surface finishes.
Q3: What are the main cutting advantages of a 91-degree approach angle (F) inside internal bores?
A3: The 91-degree lead angle is specifically engineered to square up tight internal corners and steps while directing cutting forces axially straight down the bar core. This directional alignment drastically reduces radial force (push-away), which is the absolute primary cause of chatter and dimension variation during extended 180mm extended-reach cycles.
9. Technical Maintenance & Troubleshooting Guidelines
Equivalent Industry Models
Interchangeable globally with standard international metric S18Q-STFNR16 boring tool holder assemblies. For American imperial lathe turrets, this 18mm transitional metric steel bar functions perfectly within specialized reduction sleeves, utilizing ANSI indexable insert designations **TNMG 331** or **TNMG 332**.
Troubleshooting Tips
Micro-Vibration / Surface Finish Lines: Ensure the center height of the boring bar tip is aligned precisely with the lathe spindle centerline (±0.1mm). Incorrect centerline height changes the active cutting clearance angle, accelerating nose wear.
Screw Binding Prevention: Due to localized thermal expansion during continuous cycles, clean the pocket and apply standard anti-seize paste compound to the M3.5 Torx hardware threads regularly.
Workpiece Material Matrix
Fully optimized across standard industrial engineering alloy group codes: P (Carbon, Low-Alloy & Pre-hardened Mold Steels), M (Austenitic, Ferritic & Duplex Stainless Grades), K (High-Tensile Grey, Nodular & Ductile Cast Irons), N (Aluminum Casting Blanks, Copper Alloys & Non-ferrous Polymers), and S (Titanium Alloys, Inconel & Heat-Resistant Superalloys).
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.
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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.