The Annular Bearing Engineers' Committee scale, more commonly referred to as the ABEC scale, is an industry-accepted standard for the dimensional control and manufacturing tolerances of ball bearings. Keeping the ABEC system in mind, bearing manufacturers assign an ABEC rating to their bearings to classify the different tolerance ranges for bearings. This standard rating does not consider other bearing aspects such as noise, torque, lubrication, radial play, ball complement, and so on. This system includes the dimensional control tolerances of the ball bearings inner ring, outer ring and ring width. NMB follows the specifications of the American Bearing Manufacturers Association (ABMA) and its associated ball bearing technical committee, the Annular Bearing Engineers' Committee (ABEC). These tolerances are reviewed regularly and updated as required.
Bearings rated with the ABEC rating system typically have five ratings in the class scale that range from the widest tolerances to the tightest tolerances of the bearings with rating numbers of 1, 3, 5, 7, and 9. Each number corresponds to a degree of roundness in the outer and inner races of a bearing. The higher the rating number of bearings, the tighter the component parts for tolerance, meaning that a higher ABEC grade is assigned to a ball bearing manufactured against a higher standard of precision. For instance, a ball bearing rated at a grade of 9 provides the highest precision and efficiency.
A ball bearing rated under the Annular Bearing Engineers' Committee system is typically called a precision bearing. Those bearings that do not conform to a class rating of at least 1 are not precision bearingsThe bearings rating scale makes it easy for users to make a decision as to which type of bearings they need for their applications. For critical applications that require smooth operation and optimal performance users need to look at ABEC bearings with high grades. Super precision class bearings are used in high spindle bearings, grinding spindles, aerospace, medical industry, military, and many more applications. Ball bearings that have a lower grade are more commonly used for standard everyday applications like electric motors, industrial machinery, gear boxes, skates, fishing reels, automotive, hobbies, and so on. The majority of applications can be effectively handled using a standard precision ball bearing. A standard bearing in this case is one that is in such worldwide demand that large volumes are produced. This virtually guarantees continuity of supply while assuring pricing benefits.
There are no material specifications in the rating system, but some of the options for materials to consider when purchasing a ball bearing include chrome, stainless steel, ceramic balls, etc.
Apart from the Annular Bearing Engineers' Committee rating system, there are other standards used to measure the tolerance of a ball bearing. These standards include The International Standards Organization (ISO) and the American National Standards Institute (ANSI).