Abstract: In a machine of the kind in which an operative member under the actuation of driving means is reciprocatable relative to a guide member in order to exert forces in a predetermined direction on a workpiece, toothed and elongate roller bodies having their axes of rotation extending perpendicularly to said direction are interposed between the guide member and the operative member in order to prevent the latter from tilting. The teeth of each roller body mesh with the teeth of racks extending in said direction of movement of the operative member and being provided on both the guide member and the operative member in a manner to cause each roller body to transmit under torsional strain balancing forces in its axial direction. The roller bodies also have cylindrical surface portions being coaxial with and having the same diameter as the pitch circles of their teeth, said cylindrical portions being in rolling contact with rollways provided on both the operative member and the guide member.