The Reducer,boss, cataloged under National Stock Number 4730-00-403-4358, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Sae International Dba Sae International. Government technical data includes 16 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-403-4358 |
| Primary Part Number | MS21915-5-4 |
| Item Name | Reducer,boss |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Sae International Dba Sae International |
| Status | ACTIVE |
| Surface Treatment Document and Classification | QQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OUTSIDE |
| Surface Treatment Document and Classification | QQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE INSIDE |
| Connection Style | EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END |
| Connection Style | GASKET SEAL (BOSS) FIRST END |
| Nominal Overall Length | 1.281 INCHES IN |
| Connection Type | THREADED INTERNAL BOSS FIRST END |
| Connection Type | THREADED EXTERNAL BOSS SECOND END |
| Material Document and Classification | QQ-S-637 FED SPEC 1ST MATERIAL RESPONSE AND QQ-S-637 FED SPEC 2ND MATERIAL RESPONSE AND MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE AND MIL-S-5626 MIL SPEC 4TH MATERIAL RESPONSE OVERALL |
| Nominal Thread Size | 0.438 INCHES SECOND END IN |
| Nominal Thread Size | 0.500 INCHES FIRST END IN |
| Surface Treatment | CADMIUM OUTSIDE |
| Surface Treatment | CADMIUM INSIDE |
| Thread Class | 3B FIRST END |
| Material | STEEL COMP 1137 OR STEEL COMP 1141 OR STEEL COMP 4130 OR STEEL COMP 4140 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS |
| Reducer Type | CONCENTRIC |
| 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 |
|---|---|
| MS21915-5-4 PRIMARY | Sae International Dba Sae International (USA) |
| Reference | Meaning |
|---|---|
| AS18280 | 5/9 Secondary reference U.S. Government activity |
| AS21915 | 3/1 Design control — primary reference Sae International Dba Sae International |
| MS21915-5-4 | 5/9 Secondary reference U.S. Government activity |
| MS21915-5-4 | 5/9 Secondary reference U.S. Government activity |
| AS21915 | 5/9 Secondary reference U.S. Government activity |
| AS18280 | 3/1 Design control — primary reference Sae International Dba Sae International |
NSN 4730-00-403-4358 is a Reducer,boss, manufactured by Sae International Dba Sae International, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-403-4358 has 1 manufacturer part number on file: MS21915-5-4 (Sae International Dba Sae International).
Key specifications for MS21915-5-4: Surface Treatment Document and Classification: QQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OUTSIDE; Surface Treatment Document and Classification: QQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE INSIDE; Connection Style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END; Connection Style: GASKET SEAL (BOSS) FIRST END. 16 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.