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67 Series
Home Deep Groove Ball Bearings 67 Series

6704 Open Thin Section Deep Groove Ball Bearing For Semiconductor | 20×27×4 mm

6704 Open Thin Section Deep Groove Ball Bearing For Semiconductor | 20×27×4 mm

The 6704 is an ultra-lightweight, unsealed single row ball bearing designed for applications where maximum rotational speed and absolute minimum frictional resistance are required. Featuring a classic open architecture, this thin-wall bearing provides direct access to the rolling elements, making it ideal for machinery equipped with continuous oil circulation or oil bath lubrication systems. With its highly compact 20mm bore, 27mm outer diameter, and 4mm width, the 6704 serves as a foundational component for internal, highly protected mechanical assemblies where space is at a premium.

6704 Deep Groove Ball Bearing 220×27×4 mm | ISO 67 Series | Unrestricted High-Speed Rotation

Engineered to accommodate moderate radial loads and light axial forces, this miniature bearing is stripped of all contact seals and shields to eliminate dragging friction entirely. Because it operates without the thermal constraints of rubber or metal closures, the open 6704 achieves the highest possible speed ratings in its class—up to 26,000 r/min when utilizing oil lubrication. It is the perfect choice for integration into enclosed gearboxes, cleanroom robotics, and precision instruments operating in controlled, contaminant-free environments.

6704 Open Thin Section Deep Groove Ball Bearing For Semiconductor | 20×27×4 mm

Comprehensive Applications

Highly recommended for sophisticated, clean-environment technologies where engineers need to aggressively minimize weight and maximize rotational efficiency:

Semiconductor & Cleanroom Equipment
  • Wafer Handling Robots
  • Vacuum Chamber Actuators
  • Cleanroom Conveyor Mechanisms
  • High-Speed Spindle Motors
Advanced Optics & Instrumentation
  • Telescope and Gimbal Mounts
  • Internal Laser Targeting Systems
  • Precision Rotary Encoders
  • Medical Imaging Scanners
Micro-Mechanics & Aerospace
  • Miniaturized Internal Gearboxes
  • Drone (UAV) Internal Flight Control Systems
  • Gyroscopic Stabilizers
  • Ultra-Light Electromechanical Actuators

Key Performance Features

01. Zero Contact Friction for Ultimate Speeds

By removing seals and shields, the open 6704 eliminates the drag inherently caused by closure components. This allows the bearing to run exceptionally cool and efficiently, translating to significantly higher maximum RPMs and extending the lifespan of the surrounding motor or drive system.

02. Direct Lubrication Access

The unsealed raceways are fully exposed, making this bearing highly adaptable. It is perfectly suited for complex industrial designs that utilize continuous oil mist, oil circulation, or specialized greasing systems, ensuring the internal rolling elements are constantly flushed and cooled.

03. Ultra-Compact Dimensional Profile

Conforming to the strict ISO 67 dimension series, the 6704 weighs a mere 7 grams. This ultra-thin cross-section enables engineers to drastically downsize shaft and housing dimensions, facilitating the creation of lighter, more energy-efficient tech devices.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series 67 Series – Thin Section (Ultra-Light)
Basic Designation 6704
Suffix None (Open Type)
Bore Diameter (d) 20 mm
Outer Diameter (D) 27 mm
Width (B) 4 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Cage Material Stamped Steel Crown
Dynamic Load Rating (Cʳ) 0.93 kN
Static Load Rating (C₀ʳ) 0.58 kN
Limiting Speed (Grease) 22,000 r/min
Limiting Speed (Oil) 26,000 r/min
Weight (approx.) 0.007 kg (7 grams)

Interchange Part Numbers

Common equivalents across major precision bearing manufacturers include:

  • SKF: 61704
  • NSK: 6704
  • FAG6704
  • NTN: 6704
  • KOYO: 6704
  • NMB: 6704

Design & Configuration

The 6704 is supplied in an open configuration, intended for enclosed systems or environments strictly protected from dust and debris. If your mechanical design exposes the bearing to external elements, this exact dimensional profile is also available with dual metal shields (6704-ZZ) for standard protection, or double rubber seals (6704-2RS) for maximum defense against moisture.

"Specify the 6704 Open Type for your enclosed, high-speed engineering projects to achieve unparalleled rotational freedom and ultra-lightweight performance."

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The 6704 is an ultra-lightweight, unsealed single row ball bearing designed for applications where maximum rotational speed and absolute minimum frictional resistance are required. Featuring a classic open architecture, this thin-wall bearing provides direct access to the rolling elements, making it ideal for machinery equipped with continuous oil circulation or oil bath lubrication systems. With its highly compact 20mm bore, 27mm outer diameter, and 4mm width, the 6704 serves as a foundational component for internal, highly protected mechanical assemblies where space is at a premium.

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