in the filler pieces and clamping strip for the passage of the tightening screw are marginally formed by countersinking chamfering and flanging for quick positive engagement application_number US 88338978 A description the clip fastening illustrated comprises a metal strip the free ends of which are denoted 1 and 2 each of these ends is bent at three fold lines 3 4 and 5 to form a pocket receiving a filler piece 6 and 7 respectively of rectangular cross section the ends 1 and 2 of the strip carrying the filler pieces are held together in the usual way by a tightening screw 8 which allows them to be moved relatively to one another the headed end 9 of the tightening screw is adjacent the strip end 2 and the free threaded end of this screw is adjacent the strip end 1 in conformity with this the filler pieces which are shown as 6 39 and 7 39 in fig2 are of different construction although they are externally of like dimensions the filler piece 7 39 has a smooth walled central hole 10 which guides the shank of the clamping screw countersunk portions 13 and 14 of rectangular section are provided at the two ends of hole 10 respectively at the front face 11 and the rear face 12 the end 2 of the clamping strip is correspondingly cut out and the margins around these cut outs are flanged at 15 and 16 to engage in the countersunk portions as can be seen from fig1 the free edges 17 and 18 respectively of.