A new series of Shaft collars manufactured by Sterling Instrument Inc. have a built-in bearing shim spacer and feature the Fairloc integral hub fastener. These collars, identified as the S25FB9 (brass) and S25FY9 Series (303 stainless steel), are in both inch and metric sizes. They are designed to fit shafts that are 3 to 20mm in diameter. Their ODs range from 11 to 38mm in diameter. The choice of Fairloc hubs permits frequent phase adjustment, timing and position adjustment while adding positive metal-to-metal fastening strength along both hub sections. The Fairloc integral hub fastener consists of two slots that are machined into the hub, one radially the other angularly, to create a transverse wedge which remains attached to the solid portion of the hub on one side. The resultant cantilevered clamping section has a tapped hole to accept a cap screw which passes through a clearance hole in the solid portion of the hub, and into a threaded hole in the transverse wedge section. As the screw is tightened, the cantilevered section clamps the shaft securely. The screw can be tightened and released repeatedly without marring the shaft or affecting its torque-transmitting abilities.
