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67 Series
Home Deep Groove Ball Bearings 67 Series

6708-ZZ Ultra-Thin Section Ball Bearing For Optical Instruments & Lightweight Machinery | 40×50×6 mm

6708-ZZ Ultra-Thin Section Ball Bearing For Optical Instruments & Lightweight Machinery | 40×50×6 mm

The 6708-ZZ is an ultra-thin section deep groove ball bearing engineered for applications where axial space is severely limited yet reliable rotary support is required. Featuring double metal shields (ZZ), this configuration provides effective protection against coarse debris while maintaining minimal frictional torque for high-speed operation. With a 40mm bore, 50mm outer diameter, and an exceptionally slim 6mm width, it is the preferred solution for optical instruments, medical imaging equipment, and lightweight conveyor rollers where compact packaging cannot compromise rotational precision.

6708-ZZ Deep Groove Ball Bearing 40x50x6 mm | Metric Ultra-Thin Section | Double Shielded

Manufactured to ISO dimensional standards, the 6708-ZZ utilizes a minimal cross-section design that delivers reliable load capacity within a highly constrained envelope. The deep groove geometry accommodates moderate radial loads and bidirectional axial thrust while the non-contact metal shields retain lubricating grease without adding significant drag. This combination makes the bearing ideal for applications demanding high rotational speeds in space-sensitive assemblies.

 

6708-ZZ Ultra-Thin Section Ball Bearing For Optical Instruments & Lightweight Machinery | 40×50×6 mm

Comprehensive Applications

Well-suited for precision equipment and lightweight machinery across multiple sectors:

Optical & Imaging Equipment
  • Laser scanning mirror mounts
  • Optical encoder shaft supports
  • Medical imaging gantry rollers
  • Surveillance camera pan-tilt mechanisms
Office & Consumer Devices
  • High-speed printer paper feed rollers
  • Copier drum support assemblies
  • Compact scanner transport systems
  • Small appliance drive shafts
Industrial Light Machinery
  • Light-duty conveyor rollers
  • Textile thread guide pulleys
  • Packaging film tensioning rollers
  • Small diameter idler pulleys
Precision Instruments
  • Laboratory centrifuges
  • Measuring instrument rotary stages
  • Semiconductor handling equipment
  • Miniature actuator assemblies

Key Performance Features

01. Ultra-Thin Section for Space-Constrained Designs

With a cross-section of just 6mm, the 6708-ZZ enables engineers to reduce overall assembly width significantly. Despite its slim profile, the bearing maintains full deep groove ball bearing functionality, supporting both radial and axial loads within a footprint that conventional bearings cannot accommodate. This makes it essential for modern miniaturized equipment designs.

02. Shielded Configuration for High-Speed Efficiency

The ZZ designation indicates double non-contact metal shields constructed from pressed steel. Unlike contact seals, these shields create a narrow labyrinth gap that protects against coarse contaminants while introducing virtually no additional frictional torque. This configuration allows the 6708-ZZ to achieve higher limiting speeds compared to sealed variants, making it suitable for continuous high-speed rotation.

03. Precision Manufacturing for Smooth Rotation

Constructed from high-carbon chromium steel (GCr15 / SAE 52100), the 6708-ZZ undergoes precision grinding to achieve tight geometric tolerances. The carefully controlled internal clearance and smooth raceway finish ensure consistent rotational accuracy, minimizing vibration and noise in sensitive optical and measurement applications.

Technical Specifications

Bearing Type Single Row Deep Groove Ball Bearing
ISO Dimension Series 6700 Series (Ultra-Thin Section)
Basic Designation 6708
Suffix ZZ (Double Non-Contact Metal Shields)
Bore Diameter (d) 40 mm
Outer Diameter (D) 50 mm
Width (B) 6 mm
Material (Races & Balls) Chrome Steel (GCr15 / SAE 52100)
Precision Class Standard / P5 Grade Available
Shield Material Pressed Steel
Dynamic Load Rating (Cʳ) 4.5 kN
Static Load Rating (C₀ʳ) 4.0 kN
Limiting Speed (Grease) 10,000 - 12,000 r/min
Limiting Speed (Oil) --
Weight (approx.) 0.02 kg

Interchange Part Numbers

Direct replacement for industry-standard bearings:

  • SKF: 6708-2Z
  • NSK: 6708ZZ
  • FAG6708-C-2Z
  • NTN: 6708ZZ
  • KOYO: 6708ZZ
  • TIMKEN: 6708ZZ

Design & Configuration

The 6708-ZZ is supplied with double pressed steel shields as standard, offering an optimal balance of contaminant protection and low frictional torque for high-speed applications. For environments requiring isolation from fine dust or moisture, a contact rubber seal variant (6708-2RS) is available. Stainless steel (AISI 440C) versions are offered for applications involving corrosive exposure, and C3 clearance options accommodate assemblies where thermal expansion may affect internal clearance.

"Designed for the evolving demands of compact optical systems and lightweight industrial equipment, the 6708-ZZ delivers precision rotation within an ultra-thin envelope that redefines space efficiency."

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