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R Series
Home Deep Groove Ball Bearings R Series

R2A-ZZ Shielded Miniature Ball Bearing | Heavy-Duty Micro Rotation | 3.175 × 12.7 × 4.366 mm

R2A-ZZ Shielded Miniature Ball Bearing | Heavy-Duty Micro Rotation | 3.175 × 12.7 × 4.366 mm

The R2A-ZZ is a specialized imperial miniature ball bearing designed for applications that require a small 1/8-inch bore but demand higher load-bearing stability than standard micro-bearings. Featuring an exceptionally robust 1/2-inch outer diameter relative to its bore size, the R2A-ZZ offers enhanced structural rigidity and radial strength. The double-shielded ("ZZ") configuration utilizes two non-contact metal plates to retain high-performance lubricant while acting as a barrier against dust and environmental contaminants, making it a reliable choice for high-speed, maintenance-free operation.

R2A-ZZ Deep Groove Ball Bearing R Series – Enhanced Radial Support & Shielded Longevity

Engineered for precision and durability, the R2A-ZZ excels in mechanical assemblies where rotational torque must remain low but the assembly is subject to continuous cycling. The metal shields are precision-fitted to provide maximum protection without causing the friction drag often found in contact seals. This allows the R2A-ZZ to maintain high-velocity stability and thermal efficiency. Whether utilized in specialized aerospace sensors or heavy-duty RC motor assemblies, this bearing provides a smooth, frictionless interface that maximizes the lifespan of your hardware.

R2A-ZZ Shielded Miniature Ball Bearing | Heavy-Duty Micro Rotation | 3.175 × 12.7 × 4.366 mm

Comprehensive Applications

Optimized for mechanical designers and industrial engineers requiring a high-strength 1/8-inch shaft solution:

Precision Instrumentation & Aviation
  • Meteorological Data Recorders
  • Aviation Cockpit Instruments
  • Small-Scale Gyroscopic Units
  • Telemetry Tracking Sensors
Industrial Automation & Robotics
  • High-Torque Miniature Stepper Motors
  • Precision Tensioning Pulleys
  • Robotic Arm Joint Actuators
  • Automated Sorting Conveyor Parts
High-End Consumer & Hobbyist Tech
  • High-Performance Brushless DC Motors
  • Professional-Grade RC Vehicle Hubs
  • Specialized Fishing Reel Internals
  • Commercial Power Tool Cooling Systems

Key Performance Features

01. Precision ZZ Shielding System

The R2A-ZZ features two pressed-steel shields that create a protected internal environment. This "lubricated-for-life" design prevents the ingress of grit and debris, ensuring that the rolling elements move freely within the raceways. This architecture is ideal for enclosed systems where manual relubrication is difficult or impossible.

02. Refined GCr15 Chrome Steel Construction

Forged from premium-quality GCr15 Chrome Steel (SAE 52100) and machined to P5 precision tolerances, the R2A-ZZ offers superior surface finish and hardness. The optimized internal geometry allows for smooth ball circulation, reducing vibration and noise while increasing the bearing's resistance to metal fatigue and wear.

03. Robust Imperial Proportion

With a 3.175 mm (1/8") bore and a substantial 12.7 mm (1/2") outer diameter, the R2A-ZZ provides a larger cross-section than most miniature bearings. This specific geometry allows it to handle higher radial loads and provides a more stable mounting surface for 1/8-inch shaft systems in high-vibration environments.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series R Series (Miniature Imperial / Inch)
Basic Designation R2A
Suffix Options ZZ (Dual Pressed Steel Shields)
Bore Diameter (d) 3.175 mm (1/8")
Outer Diameter (D) 12.7 mm (1/2")
Width (B) 4.366 mm (11/64")
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100) or Stainless Steel (AISI 440C)
Precision Class Standard / P5 Grade Available
Cage Material Pressed Steel or Polyamide
Dynamic Load Rating (Cʳ) 0.640 kN (640 N)
Static Load Rating (C₀ʳ) 0.225 kN (225 N)
Limiting Speed (Grease) 40,000 r/min
Limiting Speed (Oil) 48,000 r/min
Weight (approx.) 0.0024 kg (2.4 grams)

Interchange Part Numbers

Cross-reference list for simplified global procurement:

  • NMB: RI-818ZZ
  • SKF: R2A-2Z
  • FAGR2A-2Z
  • NSK: R2A-ZZ
  • NTN: R2A-ZZ
  • Barden: R2A-SS
  • KOYO: R2A-ZZ

Design & Configuration

For over 15 years, Welink Bearing has specialized in matching high-precision rotational hardware to complex industrial needs. The R2A-ZZ is supplied factory-prefilled with high-speed, low-noise grease to ensure immediate operational readiness. We offer technical customization for bulk orders, including vacuum-compatible lubrication, ceramic ball upgrades, or stainless steel variants for corrosive environments.

"Achieve superior stability with the R2A-ZZ bearing—offering robust imperial precision, dual-shielded protection, and unhindered high-speed performance for your critical micro-designs.”

Download Product Catalog (PDF)

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