| THREAD SERIES DESIGNATOR | UNF |
| NOMINAL THREAD DIAMETER | 0.375 INCHES |
| THREAD QUANTITY PER INCH | 24 |
| THREAD CLASS | 2A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 1.355 INCHES MINIMUM AND |
| 1.500 INCHES MAXIMUM |
| FASTENER LENGTH | 1.438 INCHES MINIMUM AND |
| 1.500 INCHES MAXIMUM |
| MATERIAL DOCUMENT AND CLASSIFICATION | SAE ASSN STD ALL MATERIAL RESPONSES PRIMARY WASHER |
| SURFACE TREATMENT | CADMIUM OR |
| ZINC PRIMARY WASHER |
| CADMIUM OR |
| ZINC FASTENER |
| HARDNESS RATING | 40.0 ROCKWELL C MINIMUM AND |
| 50.0 ROCKWELL C MAXIMUM PRIMARY WASHER |
| HEAD STYLE | HEXAGON |
| HEAD HEIGHT | 0.270 INCHES MINIMUM AND |
| 0.295 INCHES MAXIMUM |
| WIDTH BETWEEN FLATS | 0.551 INCHES MINIMUM AND |
| 0.562 INCHES MAXIMUM |
| WASHER QUANTITY | 1 |
| PRIMARY WASHER OUTSIDE DIAMETER | 0.678 INCHES MINIMUM AND |
| 0.692 INCHES MAXIMUM |
| PRIMARY WASHER MATERIAL THICKNESS | 0.035 INCHES NOMINAL |
| SPEC/STD CONTROLLING DATA | |
| MANUFACTURERS CODE | 21450 |
| DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | 425736 |