693ZZ Shielded Miniature Ball Bearing | 3 × 8 × 4 mm

693ZZ miniature ball bearing with a 3 mm inner diameter, 8 mm outer diameter and 4 mm width. It is intended for compact mechanisms requiring rotation around a nominal 3 mm shaft.

Nominal dimensions

• Reference: 693ZZ.
• Inner diameter: 3 mm.
• Outer diameter: 8 mm.
• Width: 4 mm.
• Type: deep-groove ball bearing.
• Metal shields on both sides.
• Supplied quantity: 1 bearing.

Applications

It can be used in small pulleys, rollers, printed mechanisms, tensioners and auxiliary assemblies for 3D printers, CNC machines and robotics. Compatibility requires an 8 mm housing, 3 mm shaft and 4 mm available width.

It may appear in Prusa, RepRap, Creality, Voron and other open-source projects, but there is no universal compatibility by printer model. The printed part or bearing mount determines the correct reference.

Protection and maintenance

The ZZ designation identifies metal shields on both sides. They help protect the interior and retain lubricant but do not make the bearing watertight.

Installation precautions

An M3 screw may have the correct nominal diameter, but its thread, tolerance and unthreaded section must be checked. For consistent rotation, the inner ring should preferably run on a smooth, cylindrical and correctly aligned surface.

Another 3 mm bearing

The 623ZZ bearing measuring 3 × 10 × 4 mm has the same 3 mm bore but a larger outer diameter and is not interchangeable without checking the housing.