an apparatus for producing an improved friction - fused welded joint is provided for use with overlapping thermoplastic strap portions . in an embodiment , the gripper is caused to swing back and force with a sufficiently large stroke and with a sufficiently fast stroke to cause sufficient reciprocation to rapidly heat the thermoplastic so that the two straps are welded together while reducing the depth of the area that is melted compared to traditional methods . also , in an embodiment , a method is provided for stopping the relative motion of the two portions of straps with the portions of the plastic straps oriented in the same relative positions at the end of the welding operation as at the beginning is disclosed .