The invention relates to a side pressure piece for workpiece positioning on a base (4) provided with one or more stops, with a retaining pin which can be inserted in an opening in the base and consists of retaining head and shank, the shank consisting of a helical spring and being arranged essentially concentrically in a blind-hole-like opening in the retaining plate (4) and being secured with its end to or in the bottom of the opening. <IMAGE>
