Bearings & Mechanical

This class covers antifriction bearings — ball and roller bearings — along with drive belting and related mechanical motion components. As with the rest of the catalog, each is built to a Military Standard or federal specification that fixes its dimensions, load rating, and material, so a bearing or belt called out on a drawing can be sourced from any manufacturer building to that same spec rather than a single proprietary source.

Identification follows the same path used throughout: a spec number or part number resolves to an NSN, and the NSN’s federal record carries the component’s technical characteristics — bore, outside diameter, width, load rating for bearings; length and cross-section for belting — along with manufacturer cross-references, so a part pulled from equipment already in service can be confirmed before it’s requoted.

Bearings and belting in this class turn up in rotating machinery, ground-support equipment, and drive systems — anywhere a shaft needs to turn freely under load or a belt needs to transmit motion between two points to a fixed specification.

How do I identify an antifriction bearing by NSN vs. manufacturer part number?

A bearing’s NSN resolves to its federal record — bore and outside diameter, width, load rating, and material — independent of which manufacturer built it. A manufacturer part number identifies one company’s specific bearing; the NSN identifies the specification that bearing (and every interchangeable equivalent from other qualified manufacturers) is built to. Working from the NSN is the way to confirm interchangeability across sources.

What’s the difference between a ball bearing and a plain bearing?

A ball bearing (an antifriction bearing) uses rolling elements between the inner and outer races to reduce friction, and is the type this catalog’s Bearings, Antifriction (FSC 3110) items cover. A plain bearing has no rolling elements — it relies on a sliding surface, typically with a bushing or bearing material between the moving parts — and is specified differently as a result. Which type a drawing calls for is fixed by its spec number, not interchangeable by substitution.