p1.1 This specification covers annular ball bearings intended primarily for use in instrument and precision rotating components. Instrument and precision ball bearings should meet tolerances specified in ABMA Standard 12.2, Instrument Ball Bearings Inch Design for Classes ABEC 5P and 7P.
1.2 Intended UseBall bearings defined by this specification are intended for use in critical components of instrument systems. Such components range from air circulating blowers and drive motors through precision gear trains, gyro gimbals, and pickoffs to rate integrating spin-motors.
1.3 The specification contains many of the requirements of MIL-B-81793, which was originally developed by the Department of Defense and maintained by the Naval Air Systems Command (Navy-AS) in Lakehurst, NJ. The following government activity codes may be found in the Department of Defense, Standardization Directory SD-1.
| Preparing activity | Custodians | Review activities |
| Navy - AS | Army - AT | Army-AV |
| Navy - AS | Navy - MC, SH |
| Air Force - 99 | Air Force-84 |
| DLA - GS | |
1.4 Classification Annular ball bearings for instrument and precision rotating components shall be of the following types, as specified:
1.4.1 Type I - Annular ball bearing, for instruments and precision rotating components, deep groove, unflanged; (See Annex A1-Annex A4)
1.4.2 Type II - Annular ball bearing, for instruments and precision rotating components, deep groove, flanged; (See Annex A2-Annex A8)
1.4.3 Type III - Annular ball bearing, for instruments and precision rotating components, deep groove, unflanged, inner ring extended; (See Annex A9-Annex A12)
1.4.4 Type IV - Annular ball bearing, for instruments and precision rotating components, deep groove, flanged, inner ring extended; (See Annex A13-Annex A16)
1.4.5 Type V - Annular ball bearing, for instruments and precision rotating components, angular contact, unflanged, nonseparable, and counterbored outer ring; (See Annex A17-Annex A20)
1.4.6 Type VI - Annular ball bearing, for instruments and precision rotating components, angular contact, flanged, nonseparable, and counterbored outer ring on flange side; (See Annex A21-Annex A24)
1.4.7 Type VII - Annular ball bearing, for instruments and precision rotating components, angular contact, unflanged, separable, and stepped inner ring; (See Annex A25-Annex A28)
1.4.8 Type VIII - Annular ball bearing, for instruments and precision rotating components, angular contact, flanged, separable, and stepped inner ring; (See Annex A29-Annex A32)
1.4.9 Type IX - Annular ball bearing, for instruments and precision rotating components, angular contact, unflanged, nonseparable, and stepped inner ring. (See Annex A33-Annex A36)
1.5 Inch-Pound Specification This specification covers only the inch-pound bearings.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.
Keywords: ABEC 5P; ABEC 7P; angular contact; barrier coating; bearing void; calibration (classification); contact angle; counterbored outer ring; deep groove radial; extended inner ring; instrument bearing; nonseparable; passivation; precision bearing; separable; starting torque; stepped inner ring; ICS Number Code 21.100.10 (Plain bearings)
