0.5 in. Hex and Keyed Shaft Coupling - AndyMark, Inc
Hillman 1/8 I.D. x 3/8 O.D. Shaft Collar (10-Pack) 883551 - The Home Depot
Ruland SPK-16-F Two-Piece Clamping Shaft Collar with Keyway, Black Oxide Steel, 1.000" Bore, 1 3/4" OD, 1/2" Width, 1/4" Keyway Width: Clamp On Shaft Collars: Amazon.com: Industrial & Scientific
Amazon.com: MECCANIXITY Shaft Collar 1.57 Inch Bore Single Split Aluminum Clamping Collar Shaft Collars with Set Screw Silver Tone : Industrial & Scientific