The Screw,close Tolerance, cataloged under National Stock Number 5305-01-503-8958, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is The Boeing Company Div Defense. Government technical data includes 15 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-503-8958 |
| Primary Part Number | ST3M557-4-16 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | The Boeing Company Div Defense |
| Status | ACTIVE |
| Fastener Length | 1.454 INCHES MINIMUM AND 1.484 INCHES MAXIMUM IN |
| Thread Length | 0.469 INCHES NOMINAL IN |
| Material Document and Classification | AMS 5662 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.2500 INCHES IN |
| Head Style | OVAL COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 0.990 INCHES MINIMUM AND 1.010 INCHES MAXIMUM IN |
| Grip Diameter | 0.2490 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Internal Drive Style | HIGH-TORQUE |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | NICKEL ALLOY 718 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.3898 INCHES MINIMUM AND 0.3948 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 |
|---|---|
| ST3M557-4-16 PRIMARY | The Boeing Company Div Defense (USA) |
| 11923-4-16 | Reid Products Inc. Dba Reid Products Inc (USA) |
| HT4027-4-16 | Howmet Global Fastening Systems Inc (USA) |
| HT4027-4-16 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| Reference | Meaning |
|---|---|
| HT4027-4-16 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-503-8958 is a Screw,close Tolerance, manufactured by The Boeing Company Div Defense, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-503-8958 has 4 manufacturer part numbers on file: ST3M557-4-16 (The Boeing Company Div Defense), 11923-4-16 (Reid Products Inc. Dba Reid Products Inc), HT4027-4-16 (Howmet Global Fastening Systems Inc), HT4027-4-16 (Sps Technologies, Llc Dba PB Fasteners).
Key specifications for ST3M557-4-16: Fastener Length: 1.454 INCHES MINIMUM AND 1.484 INCHES MAXIMUM IN; Thread Length: 0.469 INCHES NOMINAL IN; Material Document and Classification: AMS 5662 ASSN STD SINGLE MATERIAL RESPONSE OVERALL; Nominal Thread Diameter: 0.2500 INCHES IN. 15 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.