floating loosely along the axis of the fastener 10 and may maintain the screw head 102 near the opening 122 when the fastener 10 is not in use the nut 130 may be threaded with interior threads to match the first threaded portion 104 of the screw 100 the nut 130 may have an interior diameter sufficiently large to permit the second threaded portion 106 of the screw 100 to pass through unrestricted in other embodiments the nut 130 may have a smaller interior diameter in such embodiments the nut 130 may be threaded past the second threaded portion 106 during assembly or the nut 130 may be fabricated in a position between the threaded portions 104 106 the nut 130 and or washer 140 may be keyed to an interior of the housing bottom 150 or otherwise rotationally retained in order to prevent rotation of the nut 130 when the screw 100 is being screwed into or out of a sub rack or other threaded component while this keying is depicted in fig1 as a square shape with rounded corners it will be understood that any shape may be employed that prevents rotation of the nut 130 within the housing bottom 150 when rotational force is applied by the screw 100 a spring or the like may also be positioned between the nut 130 and the housing bottom 150 in order to bias the nut 130 toward the screw 100 this return spring may push the nut 130 toward the upper housing 120 it will be understood that the.