| COUNTERBORE DIAMETER | 0.254 INCHES MINIMUM NUT |
| HARDNESS RATING | 36.0 ROCKWELL C MINIMUM AND 42.0 ROCKWELL C MAXIMUM |
| LOCKING FEATURE | PREVAILING TORQUE ALL METAL DESIGN |
| OVERALL HEIGHT | 0.280 INCHES MAXIMUM |
| MATERIAL DOCUMENT AND CLASSIFICATION | AMS 5756 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| MATERIAL | NICKEL ALLOY M252 OVERALL |
| NOMINAL THREAD SIZE | 0.250 INCHES |
| NUT COUNTERBORE DEPTH | 0.090 INCHES MINIMUM NUT |
| NUT STYLE | HEXAGON |
| PART NAME ASSIGNED BY CONTROLLING AGENCY | NAVY SPECIAL PROJECT |
| WASHER OUTSIDE DIAMETER | 0.416 INCHES MAXIMUM |
| WIDTH ACROSS FLATS | 0.304 INCHES MINIMUM AND 0.316 INCHES MAXIMUM |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | AMS 6304 ASSN STD SINGLE TREATMENT RESPONSE LOCKING INSERT |
| SURFACE TREATMENT | NICKEL AND ZINC LOCKING INSERT |
| TEMP RATING | 1400.0 FAHRENHEIT NOMINAL |
| THREAD CLASS | 3B |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD QUANTITY PER INCH | 28 |
| THREAD SERIES | UNJF |