Practical Bookbinding

by Paul Adam

In nearly all cases the book is trimmed after glueing, 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.

Something must be done in trimming top and bottom to prevent the groove at the back from receiving too much pressure. The simplest means is to glue a thick board on the under side of the clamp. If a piece of stout cloth has been pasted to this board, it will afterwards be easily removed from the clamp if it is lightly glued on at two places only. If cloth is not used, pieces of the board will adhere to the clamp and cause no little inconvenience.

Instead of this, there are metal plates sold which are fastened to the clamp in a simple way, either by screws or springs, and they are just as simply removed.

The bottom edge has to be cut first, as one is thus able to adjust the head—which, of course, must be rectangular—against the back gauge and then to make the bottom edge parallel. After cutting this edge, the book is turned round and the bottom edge adjusted on the back gauge so as to get the top edge ready for cutting. Whilst doing this, care must always be taken that the book is placed under the clamp so that the arrangement made for saving the groove from pressure is effective.