A helical coil is inserted into holes at an edge of a book by a machine which is adjustable for different diameters of coil. The face of the book sits on a platen and the coil is driven by a roller while the edge of the book is supported on a plurality of spine formers having an arced surface for shaping the edge of the book and an end of the book is engaged by a side lay member at an angle to incline the holes at the angle to receive the turns of the coil. The flat spine formers are carried on supports which rotate so as to allow the turns of the coil at the pitch angle to pass the spine formers. For different book thickness and coil diameter, the arced shape of the spine formers, the spine former angle and the lay angle are changed manually.