| THREAD SERIES DESIGNATOR | UNF |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| THREAD QUANTITY PER INCH | 28 |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.500 INCHES NOMINAL |
| FASTENER LENGTH | 1.525 INCHES MINIMUM AND |
| 1.555 INCHES MAXIMUM |
| MATERIAL | IRON ALLOY 660 FASTENER |
| MATERIAL DOCUMENT AND CLASSIFICATION | FF-W-84 FED SPEC SINGLE MATERIAL RESPONSE SECONDARY WASHER |
| MIL-S-5059 MIL SPEC SINGLE MATERIAL RESPONSE PRIMARY WASHER |
| AMS 5629 ASSN STD SINGLE MATERIAL RESPONSE BEARING SURFACE OF HEAD |
| QQ-W-423 FED SPEC SINGLE MATERIAL RESPONSE SPRING |
| QQ-S-763 FED SPEC SINGLE MATERIAL RESPONSE STAND-OFF |
| SURFACE TREATMENT | PASSIVATE SECONDARY WASHER |
| PASSIVATE PRIMARY WASHER |
| PASSIVATE BEARING SURFACE OF HEAD |
| PASSIVATE SPRING |
| PASSIVATE STAND-OFF |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE SECONDARY WASHER |
| QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE PRIMARY WASHER |
| QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE BEARING SURFACE OF HEAD |
| QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE SPRING |
| QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE STAND-OFF |
| MINIMUM TENSILE STRENGTH | 175000 POUNDS PER SQUARE INCH |
| HEAD STYLE | HEXAGON |
| HEAD HEIGHT | 0.172 INCHES MINIMUM AND |
| 0.190 INCHES MAXIMUM |
| WIDTH BETWEEN FLATS | 0.367 INCHES MINIMUM AND |
| 0.375 INCHES MAXIMUM |
| MATERIAL ACCOMMODATED THICKNESS | 0.625 INCHES NOMINAL |
| SPECIAL FEATURES | HARDNESS RATING 35.0 MIN. AND 43.0 MAX. ON LOCKWASHER; APPLY A SOLID FILMLUBRICANT TO THE SCREW THREADS ONLY IN ACCORD WITH MIL-L-8937 |