In nearly all cases the book is trimmed after gluing, and it is best to do this before the glue is quite set. Even in extra work books are nowadays trimmed on three sides, that is, before the book is rounded each side is cut one after the other. This method has the advantage that it is quicker, that the top and bottom corners of the round fore-edge cannot break, and that it is easy to treat every side during the process of marbling.

Of course, in the best work the book is first cut at the front, rounded, pressed, and then cut top and bottom.
Under present conditions we might completely abandon the old method of trimming with the plough, for although this is a most valuable tool, it would not pay to use it now, and the shops where it is still in use are few and far between; besides, our German machines now do the work so thoroughly and accurately that we are able to execute the highest class of work by their aid.

The machines worked by a lever are very suitable for small shops and small books. Rotary action is for heavier work and is more suitable where both heavy and light work have to be done.

The fore edge is generally trimmed first; the back of the book is carefully adjusted to the "back gauge," the back gauge is so adjusted by moving backwards and forwards that the knife comes exactly upon the point marked beforehand. The first principle to be observed in trimming is that as little as ever possible should be taken off the book. Measuring and marking for trimming are done with the dividers; the latter is called" marking for cutting." When the back gauge has been adjusted so that the points lie directly under the knife, the clamp which holds the book in position is screwed down and the machine set in motion. The book must be cut smooth and quite free from any jaggedness, and if this has not been accomplished the knife must be ground or, at least, well sharpened.

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