| THREAD SERIES DESIGNATOR | UNC |
| NOMINAL THREAD DIAMETER | 0.312 INCHES |
| THREAD QUANTITY PER INCH | 18 |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.748 INCHES MINIMUM AND |
| 0.875 INCHES MAXIMUM |
| FASTENER LENGTH | 0.859 INCHES MINIMUM AND |
| 0.891 INCHES MAXIMUM |
| MATERIAL | STEEL OVERALL |
| MATERIAL DOCUMENT AND CLASSIFICATION | FED STD 66 FED STD SINGLE MATERIAL RESPONSE OVERALL |
| SURFACE TREATMENT | CADMIUM OVERALL |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-416,TYPE 2 CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| HARDNESS RATING | 36.0 ROCKWELL C MINIMUM AND |
| 45.0 ROCKWELL C MAXIMUM OVERALL |
| MINIMUM TENSILE STRENGTH | 160000 POUNDS PER SQUARE INCH |
| HEAD STYLE | FLAT CHAMFER |
| HEAD DIAMETER | 0.429 INCHES MINIMUM AND |
| 0.438 INCHES MAXIMUM |
| HEAD HEIGHT | 0.306 INCHES MINIMUM AND |
| 0.313 INCHES MAXIMUM |
| INTERNAL DRIVE STYLE | HEXAGON |
| WIDTH ACROSS FLATS | 0.218 INCHES MINIMUM AND |
| 0.222 INCHES MAXIMUM |
| NONDEFINITIVE SPEC/STD DATA | 1 TYPE |
| DEPARTURE FROM CITED DESIGNATOR | AS MODIFIED BY HEAD,45 DEGV GROOVE AROUND SURFACE OF HD,0.345IN.DIA,0.030IN.W |
| SPEC/STD CONTROLLING DATA | |
| MANUFACTURERS CODE | 81348 |
| NON-DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | FFS86 |
| THE MANUFACTURERS DATA | |
| MANUFACTURERS CODE | 10001 |
| DESIGN CONTROL REFERENCE | 2491621 |