Abstract: A coupling includes a sleeve (E) engaged to a lead screw .COPYRGT. on one end and to a power take-off shaft from an electric motor (D) on the other end. The lead screw (C) extends into an elongated housing (A) and is threadably received for rotation within a piston (B). An insert (F) is mounted in the sleeve (E) for maintaining respective opposite overlapping ends (G) of the lead screw and the power take-off shaft. The insert is constructed of machinable plastic capable of compensating for slight misalignment while providing resiliency and reduced problems resulting from thermal expansion and contraction of the parts.