7. Trimming the Pages of your Book

Part of the Bookbinding Tutorial
by Douglas W. Jones
THE UNIVERSITY OF IOWA Department of Computer Science

You now have a book, but you'll notice that the pages don't come out even along the edge of the book opposite the spine. The innermost pages of each section stick out farther than the others, giving that side of the book a jagged edge that can make the book difficult to use.

People who do "art bookbinding" seem to like this irregularity, but for a book you intend to be used, it's worth trimming the pages to make an even face. The easy way to do this is to take the book to a place that can shear off the edges. The same shear that works for trimming off the spine of a paperback will also serve to trim the pages of the new book, so if you can have the book trimmed for only a few dollars, do so. Tell the people who are trimming the book to square up the edge before they trim it, and then take off about 1/8 inch or 3 mm. If you've got appropriate margins around your photocopies, this shouldn't cut into the images of the original pages.

Do not try to have the top and bottom trimmed! These edges of the book should be fairly flat already because you started with good square sheets of paper and punched them carefully in a jig. If they're a bit irregular, carefully banging the top and bottom of the book against a table top should square them up.

In any case, the irregularities on the top and bottom are your fault, and you cannot fix them by trimming! The thread that sews your sections to the cover reaches all the way to the top and bottom edges of your book, and trimming the edges will cut the thread!

You can make a tool to trim your own book out of a wood chisel (1/2 inch or 15 mm minimum width) and a few blocks of hardwood. You'll need to hold your book in a clamp while you trim it. I made a minimal clamp out of two planks about 3/4 inch or 2 cm thick and a few inches longer than the book. These can be held against the book using C-clamps, or holes can be drilled through the ends of the planks so that long bolts (threaded rods) and wingnuts can be used to hold the book tightly in place. I used the same clamp I made for setting the creases in my sections (see section 3).

Clamp the book (including the covers) loosely between your planks, then square up the irregular edge of the book by pressing it edge down on a tabletop. Use shims about 1/8 inch thick (2 or 3 mm) to hold the two planks back from the irregular edge (I used thin LEGO bricks from my son's collection).

The edges of the planks will define the plane along which you will trim the book, so it is important to square things up carefully. Once you have the book squared up, with the squared edge protruding the right distance from the clamps, tighten the clamps down hard, being careful not to disturb the squareness of the assembly.

Now, you're ready to plow off the rough edges with your chisel, except that you need a jig to help hold the flat of the chisel exactly in the plane of the faces of your plank clamps. Figure 7.1 shows my jig just after I've begun work on a book.

Figure 4.2:  The plowing jig against the spine of the book.

          |                   J                 |
_______   |  :          _____________           |
       |__|  :         |__           |          |
   H   |__|_/_\________|__\/\/\/\/\|_|__________|
_______|            |     ||||||||||     |
                    |  C  || || | ||  C  |
                    |     ||    | ||     |
                    |     ||      ||     |

H -- The chisel handle
C -- The two clamp jaws
J -- The hardwood jig holding the chisel

I attached the chisel to my plowing jig with a pair of countersunk wood screws that grasped the narrowest part of the shank of the chisel between the handle and flat part of the blade. Most of the flat part of the blade is countersunk into the body of the jig in a slot I cut with the same chisel. The final adjustment of the blade height is critical. I do this by trial and error, adding scraps of paper behind the chisel blade or shank, as needed, to bring the flat of the blade exactly into the plane of the bottom of the jig.

In retrospect, I should have made one jaw of the clamp about twice as thick as the other, because by the time I've plowed off half the pages, the far end of the jig holding the chisel falls off the jaw of the clamp and it's a bit harder to keep the cutting edge of the chisel exactly on the plane I'm trying to follow. The problem isn't serious enough to make me go back and make a new clamp, though.

It is crucial that your chisel be very sharp, and there must be no bevel at all on the flat side of the blade! Careless sharpening will frequently put a slight bevel on the flat side, and this will make your plowing ride up as you work across the book instead of allowing you to hold to the plane established by the jaws of your book clamp.

To plow off the edge of the book, stroke the sharp edge of the blade gently against the edge of the book, holding the flat face of the chisel (and the flat face of the jig) tightly against the jaws of the clamp. Each stroke should cut through a few pages along the full length of the book. Since the cover is in the clamp too, it might take a few strokes to make the first cut through the cover.

As your plowing continues, a pile of confetti will accumulate around you, and you will learn the best angle to hold the plowing jig and the right pressure to apply in making the cut. It is far better to apply too little pressure than too much. Trying to cut through too much paper in one stroke will stretch the paper, resulting in a rippled texture. Even more pressure will begin to tear the paper instead of slicing cleanly through it.

I usually plow my way through about 3/4 of the book from one side, then change sides and plow in through the cover from the other side. This means that I finish the in mid-book, using extremely gentle strokes towards the end in order to trim of the last few hanging bits of confetti. If the plowing rode up out of the desired plane while cutting from the first side, the final cuts made from the second side end up trimming off hair thin shreds in the area already trimmed from the first side, largely correcting the error.