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ABEC precision levels, ABEC-1, ABEC-3, ABEC-5, ABEC-7, and ABEC-9 are the equivalent to ISO precision levels P0, P6, P5, P4, and P2 respectively.
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BHR Bearings offers bearings that are capable of rotation in excess of 500,000 RPM. These are typically used in experimental and defense applications.
However, the speed capability of a bearing will depend on its size, the type and amount of lubrication used, the bearing and cage materials, precision levels and tolerances, and for how long the the maximum speed is required (among other factors).
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"Precision" and "high-precision" are generic bearing terms; however, there is no official definition for either in the bearing industry. Generally speaking, "precision" ball bearings comply with ABEC-1 and ABEC-3 tolerances while "high-precision" ball bearings comply with ABEC-5, ABEC-7, or ABEC-9 tolerances.
Some general purpose ball bearings intentionally do not comply with the ABEC precision tolerance specifications and are not graded or rated as such.
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Yes, but it depends… Generally speaking, for small bearings it is uneconomical to attempt to refurbish a bearing product. However, for larger size bearings (6 inch bore and above) there potentially could be economic gains. In particular, bearings such as slewing rings, cylindrical roller bearings, and spherical roller bearings are candidates for refurbishing. But beyond the accumulated wear there are many other factors involved in this financial decision including maintenance cycles, lubrication, MTBF, environmental considerations and more.
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The ABEC scale is an industry accepted standard for the tolerances of a ball bearing. It was developed by the Annular Bearing Engineering Committee (ABEC) of the American Bearing Manufacturers Association (ABMA). There are five classes, going from widest tolerances to tightest: 1, 3, 5, 7, and 9. Higher ABEC classes provide better precision, efficiency, and greater speed capabilities, but do not necessarily mean that the bearing can spin faster. Additionally, the ABEC rating does not specify many other critical factors, such as smoothness of the rolling contact surfaces, ball precision, and material quality.
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Standard bearing unit inserts are pre-lubed with a lithium soap grease (Shell Alvania 3S). Relubrication should be a grease with the same soap/thickener (lithium).
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For general applications a grease fill of 30% of the free space in the bearing is accepted as standard by most manufacturers. Slow speed applications in harsh environments (such as agricultural machinery) can sometimes require a larger fill. High speed applications (i.e. hand tools) can require a lesser fill. Check with NTN engineering for any special requirements.
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ABEC-3 is an ABMA tolerance class. C3 is an internal clearance specification. Fit is the relationship between the bearing bore and outside diameters to the housing bore and shaft outside diameter. Tolerance, clearance, and fit are independent dimensions, although in some cases choosing a larger internal clearance can allow you to use a tighter interference fit.
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C3 is not a fit, it is an internal clearance. Fit is how tight or loose the shaft and housing hold the bearing in place. In most electric motor rebuild applications a C3 clearance can be used in place of a normal clearance. Contact NTN engineering for other applications.
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C3 is an internal clearance, or the amount of internal free space between the rolling elements and the raceways of a bearing. P3 does not exist. P6 is an ISO tolerance class equivalent to ABEC-3, or the accuracy the bearing is manufactured to. Clearance does not affect tolerance and tolerance does not affect clearance.
