Stainless Steel Shaft Collar, Clamp Collar Style, Standard Dimension Type, 1/2 in Bore Dia./ OUTSIDE DIAMETER: 1.125 INCHES NOMINAL THICKNESS: 0.406 INCHES NOMINAL BORE DIAMETER: 0.5000 INCHES NOMINAL END ITEM IDENTIFICATION: HERCULES C-130 AIRCRAFT SCREW THREAD SERIES DESIGNATOR AND LOCATION: ALL HOLES UNC NOMINAL THREAD SIZE AND LOCATION: 0.149 INCHES ALL HOLES MATERIAL: STEEL CORROSION RESISTING STYLE DESIGNATOR: A1 PLAIN ROUND