| BEARING SURFACE TYPE | CHAMFERED |
| HARDNESS RATING | 36.0 ROCKWELL C MAXIMUM |
| INSIDE WIDTH ACROSS FLATS | 0.489 INCHES MINIMUM AND 0.502 INCHES MAXIMUM |
| LOCKING FEATURE | PREVAILING TORQUE ALL METAL DESIGN |
| MATERIAL | STEEL OVERALL |
| III PART NAME ASSIGNED BY CONTROLLING AGENCY | NUT, HEX PREV TORQ INCH GR C |
| PROPRIETARY CHARACTERISTICS | PACS |
| NOMINAL THREAD SIZE | 0.313 INCHES |
| NUT HEIGHT | 0.258 INCHES MINIMUM AND 0.273 INCHES MAXIMUM |
| NUT STYLE | HEXAGON |
| SPECIAL FEATURES | 5/16 - 18; GRADE C; ZINC PLATED TOP LOCK NUT |
| WIDTH ACROSS FLATS | 0.489 INCHES MINIMUM AND 0.502 INCHES MAXIMUM |
| SURFACE TREATMENT | ZINC AND DICHROMATE OVERALL |
| THREAD CLASS | 2B |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD QUANTITY PER INCH | 18 |
| THREAD SERIES | UNC |