The Bushing,sleeve, cataloged under National Stock Number 3120-01-528-8501, is classified within Federal Supply Class 3120 (Bearings, Plain, Unmounted) of the Bearings group. The manufacturer of record is Schroeder Industries Llc. Government technical data includes 4 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 3120-01-528-8501 |
| Primary Part Number | TB-520 |
| Item Name | Bushing,sleeve |
| FSC / FSG | 3120 / 31 — Bearings, Plain, Unmounted |
| Manufacturer | Schroeder Industries Llc |
| Status | ACTIVE |
| Body Outside Diameter | 3.8750 INCHES MINIMUM AND 4.0000 INCHES MAXIMUM IN |
| Style Designator | SPLIT, EXTERNAL FLANGE ONE END, INTERNAL FLANGE ONE END |
| Flange Width | 0.6250 INCHES NOMINAL IN |
| Material | STEEL OVERALL |
| 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 |
|---|---|
| TB-520 PRIMARY | Schroeder Industries Llc (USA) |
| D4232 ITEM-176-TB-520 | Schroeder Industries Llc (USA) |
| Reference | Meaning |
|---|---|
| D-4232 | D/9 Drawing number reference only Schroeder Industries Llc |
NSN 3120-01-528-8501 is a Bushing,sleeve, manufactured by Schroeder Industries Llc, classified under FSC 3120, Bearings, Plain, Unmounted. Status: active.
NSN 3120-01-528-8501 has 2 manufacturer part numbers on file: TB-520 (Schroeder Industries Llc), D4232 ITEM-176-TB-520 (Schroeder Industries Llc).
1 possible match (shared part number, not a government interchangeability claim): 5140-01-672-6632. Verify interchangeability with system specifications before substitution.
Key specifications for TB-520: Body Outside Diameter: 3.8750 INCHES MINIMUM AND 4.0000 INCHES MAXIMUM IN; Style Designator: SPLIT, EXTERNAL FLANGE ONE END, INTERNAL FLANGE ONE END; Overall Length: 2.8750 INCHES NOMINAL IN; Special Features: OUTSIDE FLANGE DIAMETER IS 5" AND SOME FRACTION WHICH IS NOT DETERMINABLE WITH THE TECH DATA IN POSSESION; THE OUTSIDE DIAMETER IS TAPERED WHERE THE SMALL END IN 3.8750" AND THE LARGE END IS 4.0000"; THERE IS A KEYWAY IN THE BUSHING; AND THREE CAP SCREW HOLES; AND TWO OTHER HOLES ALL AROUND THE FLANGE PORTION; THE BORE RANGE IS 1.125"- APPROXIMATELY 2.75" BUT IS A BIT UNREADABLE ON THE TECH DATA. 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.