Method for holding in its place a separate piece placed against a side surface of a basic piece, wherein an air jet is directed to the separate piece and under this influence the separate piece is pressed against the end. Means for producing the air jets are placed for example in a stationary position or the basic piece is conveyed by a transfer carriage to which the means for producing the air jets are placed and arranged to hold at least one separate piece in its place. Alternatively, the basic piece is transferred by means of a conveyor or a transfer carriage and the means for producing the air jets are placed along this route in a stationary position and are arranged to hold in its place at least one separate piece that moves along the basic piece.