Abstract: A device for attaching a plate (12) to a post (14) with a plurality of rectangular apertures (18) equally spaced about the post (14). A plurality of arms (16) are engaged in the post (14), each arm including a retaining end (30) joined to a flat portion (22) by a waist (28). The end (30) is dimensioned to pass through the longer dimension (32) of the rectangular aperture (18) but not through the shorter dimension (34) of the aperture (18). The waist is dimensioned to fit within the shorter dimension (34) of the aperture (18). The flat portion (22) of the arm (16) has a hole (24) threaded to receive a bolt (20). A leg portion (26) extends from the flat portion for contacting the plate (12). Tightening the bolts (20) clamps the plate (12) into abuttment with the post (14) and the legs (26) of the arms (16).