in the description relative terms such as u201c lower u201d u201c upper u201d u201c horizontal u201d u201c vertical u201d u201c above u201d u201c below u201d u201c up u201d u201c down u201d u201c top u201d and u201c bottom u201d as well as derivatives thereof e g u201c horizontally u201d u201c downwardly u201d u201c upwardly u201d etc should be construed to refer to the orientation as then described or as shown in the drawings under discussion these relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation terms such as u201c connected u201d u201c connecting u201d u201c attached u201d u201c attaching u201d u201c join u201d and u201c joining u201d are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece unless expressively described otherwise fig1 is a drawing that depicts a typical prior art perfect binding system in which the present invention finds use the perfect binding system 8 is employed to produce magazines catalogs brochures periodicals containing different collections of signatures for different subscribers pocket feeders 10 feed folded signatures onto a collating conveyor or gatherer 12 and when all pages comprising a magazine have been assembled on the collating conveyor they are transferred to clamps 34 on the perfect binder 14 which travel in a counterclockwise direction in an oval path the signatures 32 are clamped along one longitudinal edge so that their respective folds or backbones are directed downwardly in this orientation each group of signatures comprising a book or magazine is initially trimmed along its held longitudinal edge and is roughened.