Miniature Bearings in Chrome Steel

Chrome steel miniature bearings for shaft sizes from 1.5mm to 9mm

Dimensions and technical drawings are shown in the product tables below
See Products Variants below for stainless steel and flanged options

People sometimes refer to miniature bearings as instrument bearings or micro bearings. Their compact size and exceptional performance characteristics make them essential components in many industries. They are used in applications as varied as gyros, anemometers, flow meters, miniature gearboxes, small motors and radio controlled models.

Ball bearings are usually made of chrome steel, which is a great choice because of its strength, low-noise characteristics, and affordability. Our chrome steel range of mini ball bearings are available with a flange on the outer ring as shown in Products Variants below.

However, manufacturers only make the smallest, most precise bearings out of stainless steel. Therefore, the cost difference is negligible due to the small amount of steel used in manufacturing. You can find our smallest miniature bearings on the stainless steel miniature bearing page (see Products Variants).

Operating condition considerations for miniature chrome steel bearings

Chrome steel bearings can handle temperatures up to 120°C when used continuously, with a steel retainer and proper lubrication. They can also be used up to 150°C intermittently. At temperatures above a certain level, the strength of chrome steel bearings decreases and they experience more of a size change compared to stainless steel. Chrome steel is not ideal for use in corrosive environments, as it does not have corrosion resistance.

To protect against moisture, miniature chrome steel bearings are coated with a preventive oil. We do not suggest using chrome steel ball bearings without lubrication (dry) because they are prone to rusting.

This can even happen when they are not in use or while they are in transit due to condensation forming inside the packaging. You cannot apply the protective oil to a dry bearing. The oil would potentially find its way inside the bearing making it no longer “dry”.

Most of our chrome steel miniature ball bearings can be supplied open or with metal shields. The larger sizes may be available with rubber or Teflon contact seals or low friction non-contact rubber seals.

Open bearings are supplied with a light oil lubrication. Shielded or sealed bearings are usually supplied with grease lubrication. However, shielded bearings can be offered with instrument oil for low speed, low friction applications. Thanks to our in-house relubrication facility, these miniature bearings can be offered with customer specified oils, greases or dry lubricants.

The standard cage or retainer for a chrome steel miniature bearing is made from SPCC steel strip. A one-piece crown cage is more common for the smallest and the thinnest bearings due to space constraints.

Larger sizes have a two piece ribbon cage. Some sizes are available with a high speed TW nylon crown cage, although operating temperatures should be kept under 120°C for this retainer.

Click on INFO in the rows below to display technical information and drawings of the bearings with load and speed data. Please note that the maximum loads and speeds are used in theoretical life calculations. To ensure reasonable bearing life, it is recommended to use bearings at significantly less than the maximum load and speed ratings.

At temperatures above a certain threshold, the maximum load-bearing capacity of chrome steel decreases and it experiences more deformation than stainless steel. Moreover, the steel is not rust-resistant and should not be used in corrosive environments.

To prevent moisture from damaging chrome steel miniature bearings, manufacturers typically coat them with a protective oil. Using chrome steel bearings without lubrication is not recommended as they can rust easily. Rusting can happen when they are stored or shipped, due to moisture inside the protective packaging. Additionally, protective oil cannot be applied to a dry bearing.

Ball bearings frequently have chrome steel components due to their ability to withstand high loads and low noise performance. Additionally, chrome steel bearings are more economical compared to other materials. On the other hand, many miniature instrument bearings are typically manufactured with stainless steel.

For further information about our range of miniature bearings in chrome steel, contact a specialist today by emailing sales@smbbearings.com.

See miniature bearings metrics below.