5/8" Shoulder x 1-1/2" Shoulder Length x 1/2"-13 18-8 Stainless Steel Socket Shoulder Bolt / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.750 INCHES NOMINAL FASTENER LENGTH: 1.500 INCHES NOMINAL HEAD STYLE: C1 HEXAGON WIDTH BETWEEN FLATS: 0.312 INCHES NOMINAL SHOULDER DIAMETER: 0.625 INCHES NOMINAL NOMINAL THREAD DIAMETER: 0.500 INCHES THREAD QUANTITY PER INCH: 13 SHOULDER SHAPE: ROUND FIRST SHOULDER PART NAME ASSIGNED BY CONTROLLING AGENCY: NAVY SPECIAL PROJECT MATERIAL: STEEL COMP 302 OVERALL THREAD SERIES DESIGNATOR: UNC