| THREAD SERIES DESIGNATOR | UNC |
| NOMINAL THREAD DIAMETER | 0.312 INCHES |
| THREAD QUANTITY PER INCH | 18 |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 1.389 INCHES MAXIMUM |
| FASTENER LENGTH | 2.0 INCHES NOMINAL |
| MATERIAL | STEEL UNS K03104 FASTENER |
| MATERIAL DOCUMENT AND CLASSIFICATION | MIL-F-18240 MIL SPEC SINGLE MATERIAL RESPONSE LOCKING FEATURE |
| ASTM A574 ASSN STD SINGLE MATERIAL RESPONSE FASTENER |
| SURFACE TREATMENT | ZINC AND |
| CHROMATE FASTENER |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | ASTM B633 TY 2 ASSN STD SINGLE TREATMENT RESPONSE FASTENER |
| HARDNESS RATING | 38.0 ROCKWELL C MINIMUM AND |
| 45.0 ROCKWELL C MAXIMUM FASTENER |
| MINIMUM TENSILE STRENGTH | 180000 POUNDS PER SQUARE INCH |
| MINIMUM YIELD STRENGTH | 155000 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 |
| LOCKING FEATURE | PATCH THREADS |
| PART NAME ASSIGNED BY CONTROLLING AGENCY | SCREW, CAP, SOCKET HEAD, SELF LOCKING |