F688ZZ flanged ball bearing – 8 × 16 × 5 mm, 18 mm flange

The F688ZZ is a flanged radial ball bearing with an 8 mm inner diameter and metal shields on both sides. Its integrated flange provides an axial shoulder against the edge of a housing and helps prevent the bearing from being inserted completely into it.

It can be used in 3D printers, CNC machines, extruders, guide pulleys, small mechanisms, wheels and automation projects, provided that its dimensions and operating conditions are suitable for the design.

Nominal F688ZZ dimensions

• Inner diameter: 8 mm.
• Bearing body outer diameter: 16 mm.
• Bearing width: 5 mm.
• Flange outer diameter: 18 mm.
• Nominal flange thickness: 1 mm.
• Type: flanged radial ball bearing.
• Protection: ZZ metal shields on both sides.

These are the usual nominal dimensions for the F688ZZ reference. Because the specific manufacturer is not identified, tolerances, internal clearance, factory lubrication and load capacity may vary between batches. If the housing fit is critical, measure the received unit before machining it.

Purpose of the flange

The flange provides a shoulder against one side of the housing and simplifies bearing positioning during installation. However, it should not automatically be considered a replacement for every axial retaining system. Clips, covers, spacers or additional fasteners may still be required depending on load direction and assembly design.

Compatibility and installation

Compatibility requires an 8 mm shaft, a housing for the 16 mm bearing body, 5 mm of available width and sufficient clearance for the 18 mm flange. Matching only the inner diameter does not guarantee direct replacement compatibility with another bearing.

• Use a shaft or screw with the appropriate diameter and fit.
• Apply installation force only to the ring being fitted.
• Do not transmit pressing force through the balls.
• Avoid deforming the side metal shields.
• Ensure that the flange rests against a flat, burr-free surface.

The ZZ shields help limit dust ingress and retain lubricant, but they do not make the bearing watertight against water, fine particles or heavy contamination.

Flanged or non-flanged version

When the flange shoulder is not required, consider the non-flanged 688ZZ bearing, which shares the nominal 8 × 16 × 5 mm dimensions. Their external geometry is different, so they should not be considered interchangeable without checking the housing.

Package contents: 1 F688ZZ bearing.