An operator suitable for opening and closing casement windows includes a housing (e.g., a base and a cover), and an operator arm subassembly driven by a worm. The operator arm subassembly may include at least one operator arm pivotally disposed in the housing via a flanged bearing. The operator arm may define a gear. If a plurality of operator arms are present, a sun gear may be used. The flanged bearing properly aligns the components to reduce stresses encountered during use. The flanged bearing may have a base portion, a middle portion, and an upper portion in a stepped configuration. The base may engage the base of the housing. The upper portion of the bearing may engage a cover of the housing. A middle portion of the bearing pivotally joins the arm and/or sun gear. The instant flanged bearing provides a smoother, more efficient operation and increases the useful life of the operator.