| DEPARTURE FROM CITED DESIGNATOR | AS MODIFIED BY FASTENER LENGTH |
| FASTENER LENGTH | 1.609 INCHES MINIMUM AND 1.656 INCHES MAXIMUM |
| HARDNESS RATING | 36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL |
| HEAD DIAMETER | 0.365 INCHES MINIMUM AND 0.375 INCHES MAXIMUM |
| HEAD HEIGHT | 0.244 INCHES MINIMUM AND 0.250 INCHES MAXIMUM |
| HEAD STYLE | FLAT CHAMFER |
| INTERNAL DRIVE STYLE | HEXAGON |
| MATERIAL DOCUMENT AND CLASSIFICATION | 66 FED STD SINGLE MATERIAL RESPONSE OVERALL |
| MATERIAL | STEEL OVERALL |
| MINIMUM YIELD STRENGTH | 130000 POUNDS PER SQUARE INCH |
| MINIMUM TENSILE STRENGTH | 160000 POUNDS PER SQUARE INCH |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| NONDEFINITIVE SPEC/STD DATA | 1 TYPE |
| WIDTH ACROSS FLATS | 0.188 INCHES NOMINAL |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-Z-325,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| SURFACE TREATMENT | ZINC OVERALL |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 1.000 INCHES MINIMUM |
| THREAD QUANTITY PER INCH | 20 |
| THREAD SERIES DESIGNATOR | UNIFIED NATIONAL COARSE (UNC) |