Climax Part RC-062 Mild Steel, Black Oxide Plating Rigid Coupling, 5/8 inch bore, 1 1/4 inch OD, 2 inch length, 5/16-18 x 5/16 Set Screw Go to amazon.com Related posts Top shaft coupling 5/8 FeatureProvides torque transmision and alignmentCost effective coupling designEasily installed where major disassembly would otherwise be requiredTolerance: +.0005/+.0030Black oxide provides some corrosion resistance