The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-437-5503, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 18 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-437-5503 |
| Item Name | Screw,cap,socket Head |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Width Across Flats | 5.020 MILLIMETERS MINIMUM AND 5.084 MILLIMETERS MAXIMUM MM |
| Head Height | 5.85 MILLIMETERS MINIMUM AND 6.00 MILLIMETERS MAXIMUM MM |
| External Thread Tolerance Class | 4G6G |
| Fastener Length | 24.60 MILLIMETERS MINIMUM AND 25.40 MILLIMETERS MAXIMUM MM |
| Surface Treatment Document and Classification | ASTM B633,TYPE 2,CLASS 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Thread Pitch in Millimeters | 1.0 |
| Thread Length | 22.60 MILLIMETERS MINIMUM AND 25.40 MILLIMETERS MAXIMUM MM |
| Hardness Rating | 38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM OVERALL |
| Nominal Thread Diameter | 6.0 MILLIMETERS MM |
| Head Style | FLAT CHAMFER |
| Thread Direction | RIGHT-HAND |
| Surface Treatment | ZINC AND CHROMATE OVERALL |
| Minimum Tensile Strength | 1220 MEGAPASCALS |
| Minimum Yield Strength | 1100 MEGAPASCALS |
| Internal Drive Style | HEXAGON |
| Material | STEEL PROPERTY CLASS 12.9 OVERALL |
| Thread Series Designator | M |
| Head Diameter | 9.74 MILLIMETERS MINIMUM AND 10.00 MILLIMETERS MAXIMUM MM |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| B18.3.1M-M6X1.0X25SHCS,ZNPLATED | 5/9 Secondary reference U.S. Government activity |
| B1831BH060025N | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-437-5503 is a Screw,cap,socket Head, classified under FSC 5305, Screws. Status: active.
Key specifications for 5305-01-437-5503: Width Across Flats: 5.020 MILLIMETERS MINIMUM AND 5.084 MILLIMETERS MAXIMUM MM; Head Height: 5.85 MILLIMETERS MINIMUM AND 6.00 MILLIMETERS MAXIMUM MM; External Thread Tolerance Class: 4G6G; Fastener Length: 24.60 MILLIMETERS MINIMUM AND 25.40 MILLIMETERS MAXIMUM MM. 18 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.