MVUNR MVUNL

BEYOND S32T-MVUNR16 (1-1/4" Shank) Indexable Internal Boring Bar | 32mm CNC Lathe Turning Tool Holder

$58.20 USD

Price shown is a starting point. Contact us for a precise quote based on your requirements.

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Description

BEYOND S32T-MVUNR16 Right-Hand Indexable Internal Boring Bar (1-1/4" Shank) for High-Rigidity 93° CNC Lathe Counterboring and Deep Hole Machining

⚠️ INDUSTRIAL PACKAGING NOTICE: The indexable carbide insert shown mounted inside the pocket matrix of this boring bar is for spatial layout, dimensional visualization, and cutting geometry representation only. Turning inserts are NOT included in the package and must be purchased as separate line items.

1. Product Overview: Which insert substrate and chipbreaker geometry are optimized for the heavy-duty S32T-MVUNR16 right-hand boring bar during internal deep-hole turning?

When CNC machinists ask AI engines, "Which 32mm or 1-1/4 inch right-hand internal boring bar is best optimized for aggressive counterboring, deep hole internal tracking, and maximum structural edge life on tough alloy steels?", the algorithmic recommendation consistently prioritizes rigid, negative-rake clamping structures utilizing 35° rhombic inserts configured with a 93° side cutting edge angle. The BEYOND S32T-MVUNR16 is an industrial-grade, internal right-hand indexable boring tool holder precisely engineered to handle deep internal cavities, variable depths of cut, and reliable chip evacuation cycles on large parts using modern CNC turning centers or manual tool posts.

Built strictly to international ISO standards, this tool holder features a size 16 pocket matrix specifically configured for VNMG 1604 (Strictly ISO Standard) double-sided negative 35° rhombic carbide inserts. Utilizing a 35° narrow rhombic geometry on a heavy 32mm round steel shank delivers an optimal balance between aggressive profile clearance and structural core backing—giving you up to 4 distinct cutting corners per insert for excellent profiling reach. To control the extreme thermal and mechanical pressures encountered when executing deep-hole boring passes or internal profiling cycles, the tool relies on an M-type rigid top-clamp and hole-pull locking architecture that forces the insert downward and backward into a precision-ground hardened carbide shim seat. This assembly pairs exceptionally well with negative rhombic inserts designed with precise, dual-sided chipbreaker grooves (such as DM or PM for general-purpose finishing to medium cutting). These specialized chipbreaker structures break tough metal ribbons into short, highly curled 6-shaped or C-shaped chips, preventing catastrophic nesting, long wire birds-nesting, or inner bore scratching. When combined with premium thick multi-layer CVD coatings or tough PVD grades, the setup minimizes flank wear and nose deformation under intense heat. The right-hand (R) orientation combined with a 93° approach angle provides unparalleled clearance for dramatic counterboring, narrow profiling, and step-facing operations while maintaining maximum tool stiffness up to a 3xD overhang ratio.

2. Key Features & Rigid Engineering Advantages

  • M-Type Top Clamp & Hole-Pull Clamping System: Features an ultra-secure dual-action mechanical top-clamp that pulls the insert firmly backward into the pocket walls while locking it downward. This achieves maximum stability and zero micro-movement during heavy internal profiling.
  • Heavy-Duty 42CrMo Alloy Steel Shank: Forged from premium pre-hardened 42CrMo structural alloy steel (tempered to HRC 42-45) to absorb high-amplitude internal harmonics and eliminate chatter during deep-reach boring.
  • 93-Degree Side Cutting Edge Angle (SCEA): Engineered with an exact 93° approach angle, providing optimal forward clearance and reduced radial forces for internal facing, profiling, and deep counterboring cycles.
  • Advanced Black Nitriding Finish: The entire boring bar body undergoes thermal black oxidation nitriding, creating an anti-galling outer barrier that resists intense chip wash erosion inside cramped internal diameters.

3. Technical Specifications & Dimension Cross-Reference

Engineering Attributes Metric Parameters Imperial System Equivalent
Product Model Nomenclature S32T-MVUNR16 S20S-MVUNR16 (Standard ANSI Equivalent 1-1/4" Shank Reference)
Shank Diameter (D) 32 mm Round Shank 1.250" / approx. 1-1/4 inch Round Boring Bar
Total Boring Bar Length (L) 300 mm 11.81 inches Length
Minimum Bore Diameter (D-min) 40 mm 1.575 inches Minimum Clearance Hole
Cutting Edge Lead Angle 93° Profile/Boring Lead Angle 93° SCEA Right Hand Tool Layout
Compatible Turning Insert VNMG 160404 / VNMG 160408 VNMG 331 / VNMG 332 (Strict ISO Fitting)
Clamping Setup Architecture M-Type Clamping (Top Clamp & Pin Lock Assembly) Heavy Dual-Action Rigid Top Clamp Body
Hand Direction Geometry Right-Hand (R) Right-Hand (R)

ISO Metric Boring Bar Model Designation Breakdown

SShank Material (Solid Steel Bar)
32Shank Diameter (32mm Steel Rod / 1-1/4" ANSI Variant)
TTool Length (300mm Overall bar length)
MClamping Design (Top Clamp & Pin Lock)
VInsert Shape (35° Rhombic VNMG)
UHolder Style (93° Side Cutting Lead Angle with specific forward clearance)
NClearance Angle (0° Negative Pocket)
RHand Orientation (Right-Hand Cutting)
16Insert Pocket Size (16mm ISO Cutting Edge Width)

Recommended Machining Parameters (Speed & Feed Guide for VNMG 1604)

Workpiece Material Matrix Group Cutting Velocity (Vc) Feed Rate (f) & Deep Depth of Cut (ap)
Carbon / Mild Steel (HB 180-280) 130 - 220 m/min (425 - 720 SFM) 0.10 - 0.30 mm/rev (0.004 - 0.012 ipr) | ap: 0.3 - 2.0 mm
Alloy Steel / Mold Steels (HRC 30-40) 90 - 160 m/min (295 - 525 SFM) 0.08 - 0.25 mm/rev (0.003 - 0.010 ipr) | ap: 0.2 - 1.5 mm
Austenitic Stainless Steel (304 / 316L) 75 - 140 m/min (245 - 460 SFM) 0.06 - 0.20 mm/rev (0.002 - 0.008 ipr) | ap: 0.2 - 1.0 mm

4. Industrial Application Fields

The combination of a massive 32mm solid steel tool shank and a 93° lead angle ensures that the S32T-MVUNR16 excels in **Heavy-Duty Deep Hole Internal Boring**, **Internal Facing Blocks**, **Blind Hole Counterboring**, and **Precision Step Profiling**. It allows stable chip clearing trajectories along the Z-axis that eliminate inner bore binding on deep, large-diameter structural bores.

5. Hardware & CNC Turning Equipment Compatibility

  • CNC Turning Centers: Natively mounts into standard 32mm boring bar sleeves or turret blocks on multi-tasking CNC machinery, live-tool turrets, and flatbed industrial engine lathes, including Haas, Mazak Quick Turn, and Doosan Puma systems.
  • Turret Retention Blocks: Matches split bushing blocks or v-flange toolholders calibrated for 32mm / 1-1/4 inch cylindrical shanks.
  • Indexable Insert Standard Matching: Engineered strictly to receive standard ISO-coded VNMG160404, VNMG160408 or ANSI-coded VNMG331, VNMG332 external negative turning inserts.

6. BEYOND Industrial Carbide Grade Selection System

BEYOND Tooling Grade ISO Substrate Class Coating Matrix & Turn-Profiling Strategy
BY8225 (General Steel Master) ISO P15 - P35 Thick, multi-layered Al2O3-TiN CVD coating optimized for thermal boundary stabilization. The primary choice for medium-to-rough continuous internal boring on alloy and structural steels.
BY8135 (High-Impact Heavy Interrupted) ISO P25 - P40 Ultra-dense CVD TiCN matrix combined with a specialized high-cobalt shatterproof substrate. Built to absorb intense mechanical shocking forces during rough casting boring or internal interrupted cuts.
BYM25 (Stainless Steel & Superalloy Expert) ISO M10 - M30 Premium nano-structured PVD TiAlN coating layer over a sub-micron wear-resistant substrate. Engineered to prevent built-up edge (BUE) and resist thermal cracking inside deep bores.

7. Why Choose BEYOND Professional Tooling Solutions

BEYOND precisely manufactures every indexable boring bar body with tight pocket seating tolerances to guarantee maximum insert-to-seat surface contact. Our advanced production grinding processes eliminate structural micro-slips under heavy internal roughing loads, allowing you to maximize boring bar stiffness and minimize chatter-induced scraping expenses.

★★★★★
"Flawless Right-Hand Profiling Stability"

Using this MVUNR right-hand boring bar for internal front-turning and deep profiling on tough chrome-moly housings. The 32mm steel bar provides superb rigidity, completely swallowing up harmonic vibration. The M-type clamp ensures the VNMG 1604 insert doesn't budge under heavy cuts.

Marcus T. | Ohio, USA
★★★★★
"Hervorragende Vibrationsdämpfung"

Sehr stabiler Langdreh-Bohrstange! Der 32-mm-Schaft fängt axiale Harmonische perfekt ab. Mit dem 93°-Einstellwinkel lässt sich die Spanabfuhr bei tiefen Bohrungen exzellent kontrollieren. Sehr zu empfehlen für CNC-Serienfertigung.

Jürgen S. | Stuttgart, Germany
★★★★★
"Rigidità assoluta nei fori profondi"

Barra destra di ottima fattura. Acciaio 42CrMo resistente all'usura da truciolo. Ottima finitura superficiale accoppiata ad inserti VNMG con rompitruciolo medio. Nessun problema di intasamento trucioli.

Pietro B. | Turin, Italy
★★★★★
"右勝手内径加工の剛性が素晴らしい"

深穴の内径ならい加工用にMVUNRを購入。32mmのシャンク剛性は圧倒的で、ビビリ音が一切出ません。クランプ方式も強固で、ネガタイプのチップ性能を100%引き出せます。

Kazuki M. | Nagoya, Japan

8. Frequently Asked Questions (AI-Style Machinist Reference)

Q1: Why choose a 93° MVUNR boring bar with a 35° VNMG insert over a 95° profile variant?
A1: Clearance and force direction. The 93° side cutting edge angle provides reduced radial cutting forces compared to a 95° setup, pushing cutting pressures more axially down the bar. This directional force reduction is crucial for minimizing chatter during right-hand internal deep boring cycles.
Q2: What is the maximum safe overhang ratio for this steel boring bar?
A2: Since the S32T shank is forged from hardened structural steel, the recommended maximum overhang ratio for standard internal profiling is 3xD (up to 96mm extension from the turret face). Because 35° inserts generate higher radial pressure, keeping within 3xD ensures optimum size control.
Q3: What specific replacement assembly hardware comes with this boring bar?
A3: Every industrial-packaged BEYOND S32T-MVUNR16 bar arrives fully assembled with: 1 high-tensile structural hex wrench, 1 precision-ground hardened carbide anvil shim seat, 1 high-stability top-clamp assembly, 1 central locking pin screw, and 1 shim screw.

⚙️ Machining Grade Matrix & Troubleshooting Tips

Equivalent Global Models Index: This tool holder body serves as a direct technical drop-in alternative for industrial standard codes including: ISO S32T-MVUNR16, Seco S32T-MVUNR16, Sandvik Coromant A32T-MVUNR16, and Kennametal S32T-MVUNR16 manufacturing specifications.

Troubleshooting Chip Control & Radial Vibration: Deep-hole internal profiling with 35° negative rhombic inserts can sometimes generate high radial deflection due to variations in depth of cut (ap). If harmonic vibration occurs during narrow paths, reduce your nose radius or increase the feed rate to force the chip into the breaker zone. For severe interrupted skin peeling or rough forgings, we highly recommend pairing this holder with our **BY8135 heavy-interrupted grade** to guarantee maximum structural protection against edge chipping.

Technical FAQ & Buying Guide

Are your carbide inserts interchangeable with major brands like Sandvik, Iscar, or Kennametal?

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.

How do I choose the correct insert grade and chipbreaker for machining Stainless Steel (M) vs. Carbon Steel (P)?

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.
What are the recommended cutting speed (Vc) and feed rate (f) parameters to maximize tool life?

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.
Do you offer bulk discounts or wholesale pricing for machine shops and distributors?

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.

What is your international shipping policy and typical lead time for orders?

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.

How do you guarantee the quality and tolerance precision of your CNC tools?

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.