| THREAD SERIES DESIGNATOR | UNC |
| NOMINAL THREAD DIAMETER | 0.312 INCHES |
| THREAD QUANTITY PER INCH | 18 |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 1.219 INCHES MINIMUM AND |
| 1.250 INCHES MAXIMUM |
| FASTENER LENGTH | 3.844 INCHES MINIMUM AND |
| 3.875 INCHES MAXIMUM |
| MATERIAL | STEEL OVERALL |
| MATERIAL DOCUMENT AND CLASSIFICATION | 66 FED STD SINGLE MATERIAL RESPONSE OVERALL |
| SURFACE TREATMENT | ZINC OVERALL |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-Z-325,TY 2,CL 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 |
| MINIMUM YIELD STRENGTH | 130000 POUNDS PER SQUARE INCH |
| HEAD STYLE | FLAT CHAMFER |
| HEAD DIAMETER | 0.457 INCHES MINIMUM AND |
| 0.469 INCHES MAXIMUM |
| HEAD HEIGHT | 0.306 INCHES MINIMUM AND |
| 0.312 INCHES MAXIMUM |
| INTERNAL DRIVE STYLE | HEXAGON |
| WIDTH ACROSS FLATS | 0.250 INCHES NOMINAL |
| HOLE CONFIGURATION STYLE | ROUND INTERNAL HEXAGON |
| HOLE TYPE | DRILLED |
| HOLE QUANTITY | 4 |
| HOLE DIAMETER | 0.047 INCHES NOMINAL |
| NONDEFINITIVE SPEC/STD DATA | 1 TYPE |
| DEPARTURE FROM CITED DESIGNATOR | AS MODIFIED BY NO. OF DRILLED HOLES |
| SPEC/STD CONTROLLING DATA | |
| MANUFACTURERS CODE | 81348 |
| NON-DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | FFS86 |