The Bearing,plain,self-Aligning, cataloged under National Stock Number 3120-01-477-9555, is classified within Federal Supply Class 3120 (Bearings, Plain, Unmounted) of the Bearings group. The manufacturer of record is The Boeing Company Div Defense. Government technical data includes 7 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 3120-01-477-9555 |
| Primary Part Number | ST4M218M40 |
| Item Name | Bearing,plain,self-Aligning |
| FSC / FSG | 3120 / 31 — Bearings, Plain, Unmounted |
| Manufacturer | The Boeing Company Div Defense |
| Status | ACTIVE |
| Inner Member Width | 1.3300 INCHES NOMINAL IN |
| Criticality Code Justification | AGAV |
| Outer Member Width | 1.2300 INCHES NOMINAL IN |
| Style Designator | WITH INSERT AND/OR LINER |
| Bore Diameter | 2.5020 INCHES MINIMUM AND 2.5030 INCHES MAXIMUM IN |
| Material | ALUMINUM OVERALL |
| Outer Member Outside Diameter | 3.2490 INCHES MINIMUM AND 3.2500 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 | Y |
| Part Number | Manufacturer |
|---|---|
| ST4M218M40 | New Hampshire Ball Bearings Inc Div Astro Division (USA) |
| ST4M218M40 PRIMARY | The Boeing Company Div Defense (USA) |
| ST4M218M40 | Rbc Transport Dynamics Corp Div Rbc Transport Dynamics (USA) |
| Reference | Meaning |
|---|---|
| ST4M218M40 | 5/2 Secondary reference U.S. Government activity |
| KSAD40-11 | 3/2 Design control — primary reference U.S. Government activity |
| AKSB40-4001 | 5/1 Secondary reference New Hampshire Ball Bearings Inc Div Astro Division |
| 03-823-40E-009 | 5/1 Secondary reference Rbc Transport Dynamics Corp Div Rbc Transport Dynamics |
NSN 3120-01-477-9555 is a Bearing,plain,self-Aligning, manufactured by The Boeing Company Div Defense, classified under FSC 3120, Bearings, Plain, Unmounted. Status: active.
NSN 3120-01-477-9555 has 3 manufacturer part numbers on file: ST4M218M40 (New Hampshire Ball Bearings Inc Div Astro Division), ST4M218M40 (The Boeing Company Div Defense), ST4M218M40 (Rbc Transport Dynamics Corp Div Rbc Transport Dynamics).
Key specifications for ST4M218M40: Inner Member Width: 1.3300 INCHES NOMINAL IN; Criticality Code Justification: AGAV; Outer Member Width: 1.2300 INCHES NOMINAL IN; Style Designator: WITH INSERT AND/OR LINER. 7 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.