| THREAD SERIES DESIGNATOR | UNC |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| THREAD QUANTITY PER INCH | 20 |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.418 INCHES MINIMUM AND |
| 0.438 INCHES MAXIMUM |
| FASTENER LENGTH | 1.918 INCHES MINIMUM AND |
| 1.938 INCHES MAXIMUM |
| MATERIAL | STEEL OVERALL |
| MATERIAL DOCUMENT AND CLASSIFICATION | NASM 21472 NATIONAL STD/SPEC SINGLE MATERIAL RESPONSE OVERALL |
| SURFACE TREATMENT | ZINC OVERALL |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | ASTM B 633, TYPE II, CLASS FE/ZN 5 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| HEAD STYLE | FLAT CHAMFER |
| HEAD DIAMETER | 0.419 INCHES MINIMUM AND |
| 0.438 INCHES MAXIMUM |
| HEAD HEIGHT | 0.183 INCHES NOMINAL |
| CHAMFER ANGLE | 30.0 DEGREES MINIMUM AND |
| 45.0 DEGREES MAXIMUM |
| INTERNAL DRIVE STYLE | HEXAGON |
| WIDTH ACROSS FLATS | 0.156 INCHES NOMINAL |
| SHOULDER SHAPE | ROUND ALL SHOULDERS |
| SHOULDER DIAMETER | 0.3085 INCHES MINIMUM AND |
| 0.3105 INCHES MAXIMUM ALL SHOULDERS |
| SHOULDER LENGTH | 1.500 INCHES NOMINAL ALL SHOULDERS |
| SPECIFICATION/STANDARD DATA | 80205-NASM51975 NATIONAL STD/SPEC |