| THREAD SERIES | UNC |
| NOMINAL THREAD SIZE | 0.250 INCHES |
| THREAD QUANTITY PER INCH | 20 |
| THREAD CLASS | 2B |
| THREAD DIRECTION | RIGHT-HAND |
| MATERIAL | STEEL NUT |
| STEEL COMP 1050 WASHER |
| MATERIAL DOCUMENT AND CLASSIFICATION | LOW CARBON STEEL MFR REF SINGLE MATERIAL RESPONSE NUT |
| AISI 1050 OR EQUIVALENT MEDIUM CARBON STEEL ASSN STD SINGLE MATERIAL RESPONSE WASHER |
| SURFACE TREATMENT | ZINC OVERALL |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | FE/ZN 3AT PER ASTM F1941 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| NUT STYLE | HEXAGON |
| WASHER OUTSIDE DIAMETER | 0.494 INCHES MINIMUM AND |
| 0.506 INCHES MAXIMUM |
| OVERALL HEIGHT | 0.178 INCHES MINIMUM AND |
| 0.193 INCHES MAXIMUM |
| WIDTH ACROSS FLATS | 0.423 INCHES MINIMUM AND |
| 0.438 INCHES MAXIMUM |
| LOCKING FEATURE | PREVAILING TORQUE ALL METAL DESIGN |
| PART NAME ASSIGNED BY CONTROLLING AGENCY | 1/4"-20 ZINC FINISH GRADE KEPS LOCK NUT WITH EXTERNAL TOOTH LOCKWASHER |