| FASTENER LENGTH | 3.535 INCHES MINIMUM AND 3.565 INCHES MAXIMUM |
| HARDNESS RATING | 36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL |
| HEAD HEIGHT | 0.156 INCHES MINIMUM AND 0.171 INCHES MAXIMUM |
| HEAD STYLE | DISHED HEXAGON |
| MATERIAL DOCUMENT AND CLASSIFICATION | MIL-B-7838 MIL SPEC ALL MATERIAL RESPONSES OVERALL |
| MATERIAL | STEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OR STEEL COMP 8735 OR STEEL COMP 6150 OVERALL |
| MINIMUM TENSILE STRENGTH | 160000 POUNDS PER SQUARE INCH |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| SHOULDER DIAMETER | 0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM FIRST SHOULDER |
| SHOULDER LENGTH | 3.115 INCHES MINIMUM AND 3.135 INCHES MAXIMUM FIRST SHOULDER |
| SHOULDER SHAPE | ROUND FIRST SHOULDER |
| WIDTH BETWEEN FLATS | 0.492 INCHES MINIMUM AND 0.502 INCHES MAXIMUM |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-416,TYPE 2 CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| SURFACE TREATMENT | CADMIUM AND CHROMATE OVERALL |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.400 INCHES MINIMUM AND 0.450 INCHES MAXIMUM |
| THREAD QUANTITY PER INCH | 28 |
| THREAD SERIES DESIGNATOR | UNF |