The Bearing,plain,self-Aligning, cataloged under National Stock Number 3120-01-133-7939, is classified within Federal Supply Class 3120 (Bearings, Plain, Unmounted) of the Bearings group. The manufacturer of record is New Hampshire Ball Bearings Inc Div Astro Division. Government technical data includes 4 specifications, cited from the U.S. Government catalog. The record lists 4 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 9 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 3120-01-133-7939 |
| Primary Part Number | ST4M218M30A |
| Item Name | Bearing,plain,self-Aligning |
| FSC / FSG | 3120 / 31 — Bearings, Plain, Unmounted |
| Manufacturer | New Hampshire Ball Bearings Inc Div Astro Division |
| Status | ACTIVE |
| Inner Member Width | 1.1700 INCHES MINIMUM AND 1.1750 INCHES MAXIMUM IN |
| Outer Member Width | 1.1200 INCHES MINIMUM AND 1.1300 INCHES MAXIMUM IN |
| Bore Diameter | 1.9020 INCHES MINIMUM AND 1.9025 INCHES MAXIMUM IN |
| Outer Member Outside Diameter | 2.6540 INCHES MINIMUM AND 2.6550 INCHES MAXIMUM IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| ST4M218 | The Boeing Company Div Defense (USA) |
| ST4M218M30A PRIMARY | New Hampshire Ball Bearings Inc Div Astro Division (USA) |
| ST4M218M30A PRIMARY | Rbc Transport Dynamics Corp Div Rbc Transport Dynamics (USA) |
| ST4M218M30A PRIMARY | The Boeing Company Div Defense (USA) |
| Reference | Meaning |
|---|---|
| ST4M218M30 | 5/9 Secondary reference The Boeing Company Div Defense |
| YTA390A | 5/9 Secondary reference Rexnord Industries, Llc Div Aerosspace Bearing Operation |
| KSAD30-8 | 5/9 Secondary reference U.S. Government activity |
| KSAD30-13 | 5/1 Secondary reference U.S. Government activity |
| 10108049 | 6/9 Informative reference only Nimikkeistokeskus Ncb Finland |
| ST4M218M30A | 3/2 Design control — primary reference U.S. Government activity |
| ADSB30-303 | 5/1 Secondary reference New Hampshire Ball Bearings Inc Div Astro Division |
| ADSB30-302 | 5/9 Secondary reference New Hampshire Ball Bearings Inc Div Astro Division |
| 03-823-30E-001 | 5/1 Secondary reference Rbc Transport Dynamics Corp Div Rbc Transport Dynamics |
NSN 3120-01-133-7939 is a Bearing,plain,self-Aligning, manufactured by New Hampshire Ball Bearings Inc Div Astro Division, classified under FSC 3120, Bearings, Plain, Unmounted. Status: active.
NSN 3120-01-133-7939 has 4 manufacturer part numbers on file: ST4M218 (The Boeing Company Div Defense), ST4M218M30A (New Hampshire Ball Bearings Inc Div Astro Division), ST4M218M30A (Rbc Transport Dynamics Corp Div Rbc Transport Dynamics), ST4M218M30A (The Boeing Company Div Defense).
Key specifications for ST4M218M30A: Inner Member Width: 1.1700 INCHES MINIMUM AND 1.1750 INCHES MAXIMUM IN; Outer Member Width: 1.1200 INCHES MINIMUM AND 1.1300 INCHES MAXIMUM IN; Bore Diameter: 1.9020 INCHES MINIMUM AND 1.9025 INCHES MAXIMUM IN; Outer Member Outside Diameter: 2.6540 INCHES MINIMUM AND 2.6550 INCHES MAXIMUM IN. 4 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.