The Screw,cap,hexagon Head, cataloged under National Stock Number 5305-01-273-1504, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is The American Society of Mechanical Engineers. Government technical data includes 22 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-273-1504 |
| Primary Part Number | B1821BH031C250D |
| Item Name | Screw,cap,hexagon Head |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | The American Society of Mechanical Engineers |
| Status | ACTIVE |
| Head Height | 0.195 INCHES MINIMUM AND 0.211 INCHES MAXIMUM IN |
| Fastener Length | 2.406 INCHES MINIMUM AND 2.500 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | ASTM B633 TY 2 SC 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.864 INCHES MINIMUM AND 1.052 INCHES MAXIMUM IN |
| Hardness Rating | 32.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM OVERALL |
| Hole Configuration Style | HEXAGON FLATS |
| Material Document and Classification | SAE GRADE 8 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.312 INCHES IN |
| Features Provided | FINISHED HEAD |
| Head Style | HEXAGON |
| Thread Direction | RIGHT-HAND |
| Width Between Flats | 0.489 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN |
| Nondefinitive Spec/std Data | 2 TYPE AND 10P STYLE |
| Surface Treatment | ZINC AND CHROMATE OVERALL |
| Minimum Tensile Strength | 150000 POUNDS PER SQUARE INCH LBS |
| Thread Class | 2A A |
| Thread Quantity Per Inch | 18 |
| Material | STEEL OVERALL |
| Hole Quantity | 1 |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) |
| Hole Type | DRILLED |
| Hole Diameter | 0.060 INCHES MINIMUM AND 0.068 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 |
|---|---|
| B1821BH031C250D PRIMARY | The American Society of Mechanical Engineers (USA) |
| Reference | Meaning |
|---|---|
| FF-S-85 | 4/1 Identification reference U.S. Government activity |
| MS18154-40 | 5/9 Secondary reference U.S. Government activity |
| WG103790 | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
NSN 5305-01-273-1504 is a Screw,cap,hexagon Head, manufactured by The American Society of Mechanical Engineers, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-273-1504 has 1 manufacturer part number on file: B1821BH031C250D (The American Society of Mechanical Engineers).
Key specifications for B1821BH031C250D: Head Height: 0.195 INCHES MINIMUM AND 0.211 INCHES MAXIMUM IN; Fastener Length: 2.406 INCHES MINIMUM AND 2.500 INCHES MAXIMUM IN; Surface Treatment Document and Classification: ASTM B633 TY 2 SC 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL; Thread Length: 0.864 INCHES MINIMUM AND 1.052 INCHES MAXIMUM IN. 22 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.