Method of and implement for cutting books at the backbones

摘要

The backbones of successive stacks of signatures of a series of such stacks are trimmed by a rotary implement having two annuli of substantially radially extending orbiting trimming or cutting tools. The tools of one annulus extend radially outwardly beyond the tools of the other annulus, and the tools of one annulus extend axially forwardly beyond the tools of the other annulus. The tools which extend axially forwardly beyond the other tools orbit at a higher speed. The two annuli of tools can be orbited in the same direction or in opposite directions.