Chrome steel miniature ball bearings for shaft sizes from 0.0937" to 1.00".
See the product table below for dimensions and technical drawings. For stainless steel and flanged options, see Product Variants below.
Our inch-sized miniature bearings are used in applications including gyros, anemometers, flow meters, miniature gearboxes, small motors and radio-controlled models. Also known as instrument bearings or micro bearings, these products are available in a range of sizes and configurations.
Selecting precision bearings
When selecting precision bearings, start with the dimensions and operating requirements of the assembly. This range covers imperial shaft sizes from 0.0937" to 1.00", with individual dimensions shown in the product table.
For applications requiring high precision, review the available technical information and confirm that the specification meets your requirements. Radial play options should also be considered.
Need expert advice? Email sales@smbbearings.com to arrange a call with one of our specialists.
Applications for inch-sized miniature bearings
Miniature bearings are used across a variety of instruments and small mechanisms. The applications below provide a starting point for selection; the appropriate size and configuration will depend on the requirements of the individual assembly.
Gyros, anemometers and flow meters
Instrument applications listed for this range include gyros, anemometers and flow meters. When comparing bearings for these applications, review the dimensions, lubrication options and operating conditions together.
For low-speed, low-friction applications, shielded bearings can be supplied with instrument oil. Our smallest inch-sized instrument bearings are available in the stainless steel range linked below.
Miniature gearboxes and small motors
Miniature gearboxes and small motors are further applications for these imperial bearings. Chrome steel offers high load capacity and good low-noise properties, making these characteristics useful considerations when comparing the available options.
Check the load and speed data for the individual bearing. Where higher speeds are involved, review the available retainer and lubrication options.
Radio-controlled models
Inch-sized miniature bearings are also used in radio-controlled models. Use the product table to match the required dimensions and check which open, shielded or sealed versions are available.
Where an assembly requires a flange on the outer ring, refer to the flanged product variant.
Chrome steel and stainless steel options
Chrome steel is the most common material for ball bearings because of its high load capacity, good low-noise properties and cost-effectiveness. These chrome steel bearings offer several configuration and lubrication choices across the range.
Many very small instrument bearings are manufactured only in stainless steel. They are not used in high-load applications and the small amount of material involved means the cost difference is negligible.
Our smallest inch-sized miniature bearings can be found on the stainless steel miniature bearings page. Compare the dimensions and available variants before choosing between the ranges.
Flanged miniature bearings in inch sizes
Our chrome steel inch-sized miniature bearings are also available with a flange on the outer ring.
If your assembly requires this configuration, see Product Variants below for the flanged range and its dimensions. Check the technical drawing for the selected reference to confirm that the complete bearing dimensions match your requirements.
Open, sealed and shielded configurations
Most of our imperial chrome steel miniature bearings can be supplied open or with metal shields. Larger sizes may also be available with rubber or Teflon contact seals, or low-friction non-contact rubber seals.
Open bearings are supplied with light oil lubrication. Shielded or sealed bearings are usually supplied with grease, although shielded versions can be offered with instrument oil for low-speed, low-friction applications.
Lubrication choices for your application
Lubrication is an important consideration when selecting miniature ball bearings, particularly where low friction or specific operating temperatures are required. If your aim is to reduce friction in a low-speed application, discuss the instrument oil option available for shielded bearings.
Our in-house relubrication facility allows these miniature bearings to be offered with customer-specified oils, greases or dry lubricants. See our bearing lubrication guidance for further information.
Operating temperatures and retainer options
With a steel retainer and a suitable lubricant, chrome steel bearings can operate at 120°C continuously or up to 150°C intermittently. Above these temperatures, load capacity is reduced and chrome steel undergoes greater dimensional change than stainless steel.
The standard cage or retainer is manufactured from SPCC steel strip. A one-piece crown cage is more common in the smallest and thinnest bearings because of space constraints. Larger sizes have a two-piece ribbon cage.
Some sizes are available with a high speed TW nylon crown cage. Operating temperatures must remain below 120°C for this retainer.
Corrosion protection, storage and handling
Chrome steel is not corrosion resistant, so these bearings are unsuitable for corrosive environments. A coating of preservative oil helps protect them against moisture.
We do not recommend using chrome steel bearings without lubricant. Corrosion can occur even during storage or shipping if condensation forms inside the packaging. Applying protective oil only to the outside will not keep a bearing dry internally, because the oil will find its way inside.
Click INFO in the product table to view technical drawings and load and speed data.
Maximum ratings are used in theoretical bearing life calculations. To support reasonable bearing life, we recommend operating significantly below the stated maximum load and speed ratings. Review these figures for the specific bearing before making your selection.
Where to get bearing support
Get in touch with our experienced team today by emailing sales@smbbearings.com or fill in the contact form for guidance on selecting the right bearing for your application.
