| THREAD SERIES DESIGNATOR | UNC |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| THREAD QUANTITY PER INCH | 20 |
| THREAD CLASS | 3B |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.750 INCHES NOMINAL |
| FASTENER LENGTH | 0.875 INCHES NOMINAL |
| MATERIAL | NICKEL ALLOY K-500 AND |
| NICKEL ALLOY 502 OVERALL |
| MATERIAL DOCUMENT AND CLASSIFICATION | QQ-N-286 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| HARDNESS RATING | 37.0 ROCKWELL C MINIMUM AND |
| 45.0 ROCKWELL C MAXIMUM OVERALL |
| MINIMUM TENSILE STRENGTH | 70000 POUNDS PER SQUARE INCH |
| HEAD STYLE | FLAT CHAMFER |
| HEAD DIAMETER | 0.656 INCHES NOMINAL |
| HEAD HEIGHT | 0.156 INCHES MINIMUM AND |
| 0.188 INCHES MAXIMUM |
| INTERNAL DRIVE STYLE | HEXAGON |
| WIDTH ACROSS FLATS | 0.362 INCHES MINIMUM AND |
| 0.375 INCHES MAXIMUM |
| SURFACE FINISH | 63.0 MICROINCHES BEARING SURFACE OF HEAD |
| 63.0 MICROINCHES GRIP |
| 32.0 MICROINCHES THREADS |
| SPEC/STD CONTROLLING DATA | |
| MANUFACTURERS CODE | 81349 |
| NON-DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | MIL-DTL-1222J |
| DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | M1222SN4C314NCNN |