Stainless Steel Miniature Bearings

Stainless steel miniature bearings for shaft sizes from 0.6mm to 9mm
See product table below for dimensions and technical drawings
See Products Variants below for chrome steel and flanged options

Stainless steel miniature bearings are sometimes referred to as instrument bearings or micro bearings and are used in applications as varied as clocks, wind speed measuring instruments, medical instruments, fishing reels, scanners, encoders and small drones. Stainless steel miniature bearings are also available with a flange on the outer ring. See Products Variants below for more details.

Many small, instrument bearings are only made from 440 grade stainless steel as instrument applications are not usually high load. EZO stainless steel instrument bearings are made from KS440 stainless steel, also known as ACD34 or X65Cr13. This grade of stainless steel has a greater load capacity than AISI-440C grade and better low noise qualities. It is also has better corrosion resistance.

Stainless steel bearings, with a stainless steel retainer and a suitable high temperature lubricant, can be used at temperatures of 250°C constant or up to 300°C intermittent. Above these temperatures, the load capacity of stainless steel is reduced so we recommend full ceramic bearings for use over 300°C.

Stainless steel bearings are suitable for use in mildly corrosive environments as the steel is corrosion resistant but it is affected by seawater and stronger acids or alkalis. Our marine grade stainless steel bearings, plastic bearings or full ceramic bearings should be used in very corrosive environments. Stainless steel bearings do not need preservative oil on the exterior surfaces so they can be used without lubrication (dry).

Most of our stainless steel miniature bearings can be supplied open or with AISI-304 stainless steel shields. The smallest sizes are only available open. The larger sizes may be available with rubber or Teflon contact seals or low friction non-contact rubber seals. The open miniature bearings are normally oil lubricated. Shielded or sealed bearings are generally pre-lubricated with grease but shielded bearings can also be supplied with instrument oil for low torque applications or completely dry for very low speed applications where very low rotational resistance is required. Thanks to our in-house lubrication facility, our stainless steel miniature bearings can be relubricated according to customer requirements.

The standard cage or retainer for a stainless steel miniature bearing is made from either AISI-304 or AISI-420 stainless steel. A one-piece crown cage is more common for the very small and the very thin section bearings due to space constraints. Larger sizes have a two piece ribbon cage. For higher speeds, some sizes can be supplied with a reinforced “TW” nylon crown cage although this reduces the maximum operating temperature to 120°C.

Click on INFO in the rows below to display technical drawings of the bearings with load and speed data. The load ratings shown are for AISI-440C stainless steel bearings. Load ratings are higher for EZO KS440 bearings. Please note that the maximum loads and speeds are used in theoretical life calculations. It is recommended to use bearings at significantly less than the maximum load and speed ratings to ensure reasonable bearing life.