1/2"-13 Grade C Zinc Finish Steel Top Lock Nut / THREAD CLASS: 2B THREAD DIRECTION: RIGHT-HAND LOCKING FEATURE: PREVAILING TORQUE ALL METAL DESIGN LUBRICATION: WAX NUT STYLE: A12 HEXAGON NUT HEIGHT: 0.427 INCHES MINIMUM AND 0.573 INCHES MAXIMUM END ITEM IDENTIFICATION: 4940-01-591-0265 WIDTH ACROSS FLATS: 0.736 INCHES MINIMUM AND 0.752 INCHES MAXIMUM THREAD SERIES: UNC THREAD QUANTITY PER INCH: 13 NOMINAL THREAD SIZE: 0.50 INCHES BEARING SURFACE TYPE: FLAT OR CHAMFERED PART NAME ASSIGNED BY CONTROLLING AGENCY: 1/2-13, TOP LOCK NUTS, IFI 100/107 GRADE C, ZINC PLATED MATERIAL: STEEL OVERALL SURFACE TREATMENT: ZINC OVERALL SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ASTM F1941 ASSN STD SINGLE TREATMENT RESPONSE OVERALL