based material and on whose top surface 3 a wear part 4 is mounted or made integral therewith arrangement 1 further includes a support piece 5 in accordance with the invention shaped part 2 has a 2 part t groove 7 1 representing an inside contour 6 extending along the entire length on under side 2 1 thereof on first side 6 a and a dovetail groove 8 1 made up of two halves representing an inside contour 6 on second side 6 b extending along the entire length of shaped part 2 support piece 5 on upper side 5 1 and on first side 9 a thereof includes a 2 part t rib 10 1 representing an outside contour 9 extending along the entire length thereof and a dovetail rib 11 1 on second side 9 b representing an outside contour 9 also extending along the entire length thereof a preferably controllable clamping device 12 is located in the area of angled 2 part contour 13 1 clamping device 12 however can also be designed as a non operable unit for example a spring clamp 0049 fig2 shows a schematic cross section of a second embodiment of arrangement 1 according to the second embodiment shaped part 2 has a t groove 7 as an inside contour 6 advantageously with a recess 14 in grooved bottom 15 and.