A delrin Castable Threaded Insert is available from Zest Anchors, Inc. to create a threaded site for a Locator Attachment in an implant bar or root coping. The plastic insert with a 2.0mm internal thread is surveyed into the wax pattern using a 2.0mm tap and then cast in any alloy of choice. The resulting threaded socket will allow a Locator Abutment to be torque tightened into place for retaining an overdenture.