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67 Series
Home Deep Groove Ball Bearings 67 Series

675 Open Miniature Deep Groove Ball Bearing | Zero-Shield Design for Maximum Speed | 5×8×2.5 mm

675 Open Miniature Deep Groove Ball Bearing | Zero-Shield Design for Maximum Speed | 5×8×2.5 mm

The 675 Open is an ultra-miniature, single-row ball bearing designed for high-precision applications where minimal starting torque and maximum rotational velocity are paramount. Without the added friction of seals or shields, this 5x8x2.5 mm component offers an unobstructed path for lubrication, making it ideal for systems utilizing oil mist or oil bath lubrication. With a total weight of only 0.4 grams, the 675 open type is the preferred choice for high-speed spindles, precision measuring instruments, and vacuum environments where seal outgassing or drag must be strictly avoided.

675 Deep Groove Ball Bearing 5x8x2.5 mm | 67 Series – Zero Friction & High Velocity

This unshielded micro-bearing is engineered for engineers who require the absolute lowest possible mechanical resistance. By eliminating physical closures, the 675 provides a completely free-spinning architecture, allowing it to reach industry-leading speeds of up to 60,000 r/min when lubricated with oil. It is perfectly suited for clean-room environments or enclosed mechanical assemblies where it can be continuously lubricated, ensuring fluid, vibration-free motion for the most delicate rotational tasks.

675 Open Miniature Deep Groove Ball Bearing | Zero-Shield Design for Maximum Speed | 5×8×2.5 mm

Comprehensive Applications

Specifically designed for clean, controlled environments and high-frequency oscillation devices:

High-Performance Spindles & Rotors
  • Micro High-Speed Grinding Spindles
  • Precision Gyroscopes and Gimbals
  • Turbocharger Impeller Shafts (Miniature)
  • High-Frequency Dental Handpiece Turbines
Optical & Laboratory Instrumentation
  • Laser Scanning Mirror Assemblies
  • High-Speed Centrifuge Rotors
  • Micro-Analytical Measuring Equipment
  • Clean-Room Robotics and Actuators
Aerospace & Specialized RC
  • High-End Brushless Motor Internal Support
  • Precision Navigation Systems
  • Micro Satellite (CubeSat) Mechanical Modules
  • Vacuum-Compatible Rotary Joints

Key Performance Features

01. Friction-Free Open Architecture

The 675 Open design features no contact or non-contact closures, resulting in the lowest possible rotational torque. This allows for near-instantaneous acceleration and the highest efficiency in energy-sensitive applications, making it indispensable for battery-operated micro-devices.

02. Enhanced Lubrication Versatility

Without shields, the 675 allows for direct access to the raceways. This versatility enables engineers to implement various lubrication strategies—from ultra-light oils for maximum speed to specialized greases for specific temperature ranges—and facilitates easy cleaning and re-lubrication.

03. Ultra-Thin Profile for Compact Integration

Measuring just 2.5mm in width, this bearing enables the most aggressive miniaturization of mechanical assemblies. Its lightweight GCr15 Chrome Steel construction provides high radial load capacity despite its microscopic size, offering a superior power-to-weight ratio for aerospace and micro-robotics.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series 6700 Series (Micro/Ultra-Thin Section)
Basic Designation 675
Suffix None (Open Type)
Bore Diameter (d) 5 mm
Outer Diameter (D) 8 mm
Width (B) 2.5 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Shield Material None
Dynamic Load Rating (Cʳ) 0.284 kN (284 N)
Static Load Rating (C₀ʳ) 0.108 kN (108 N)
Limiting Speed (Grease) 50,000 r/min
Limiting Speed (Oil) 60,000 r/min
Weight (approx.) 0.0004 kg (0.4 grams)

Interchange Part Numbers

Interchangeable with the following high-precision manufacturer parts:

  • SKF: 617/5
  • NSK: 675
  • FAG675
  • NTN: 675
  • KOYO: 675
  • NMB: L-850

Design & Configuration

The 675 Open bearing is the definitive solution for high-speed applications within protected, lubricated environments. Because it lacks integrated protection, it is essential to ensure your assembly is shielded from external debris. With over 15 years of expertise in the bearing industry, Welink Bearing offers expert consultation on lubrication selection and fit tolerances to ensure your precision designs operate at their theoretical peak performance.

"Maximize your system’s RPM and efficiency with the 675 Open miniature bearing, the ultimate choice for zero-drag, high-speed precision in ultra-compact designs."

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