Abutment piece adapted to be inserted in a T slot of a machine tool table

In an abutment piece adapted to be inserted in a T slot of a machine tool table and which bears against a lateral surface of a leg section of the T slot by means of an abutment surface and projects beyond the clamping surface of the machine tool table, the improvement comprising wherein the abutment piece has a head portion projecting beyond the clamping surface and the width of which is greater than the slot width of the leg section, the abutment piece has a neck portion engaging in the T slot and the width of which is smaller than the slot width, the head portion has on its side facing away from the abutment surface a bearing surface inclined at 45.degree. with respect to the abutment surface and extending toward the neck portion and by means of which the head portion is supported on the chamfered outer edge of a lateral surface of the leg section, the said outer edge adjoining the clamping surface, and on the neck portion of the abutment piece there is provided a wedge element movable parallel to the abutment surface and perpendicularly to the head portion by means of a clamping screw and engaging in the widened flange section of the T slot, the wedge surface of the said wedge element, which faces the bearing surface and is inclined at an opposite angle with respect to the abutment surface, being pressable against the inner edge of the corresponding lateral surface of the leg section.