Cutting, Attaching Boards, and Gluing in Book Binding

Every well-made hardcover book holds a hidden architecture beneath its cover. Three precise operations decide whether that book survives decades of handling or falls apart within a few years: cutting the boards to the right size, attaching them firmly to the text block, and gluing the spine so everything stays together. These steps sit at the heart of the binding process, and getting them right is what separates a durable volume from a flimsy one. This post walks through each stage so you understand not just what binders do, but why each decision matters for the long life of a book.

Board selection and cutting 🔗

The boards are the skeleton of a book’s cover. They give the volume its structure, protect the pages inside, and carry the weight of repeated opening and closing. Before any cutting happens, a binder has to choose the right board material, because the wrong choice undermines everything that follows.

Historically, binders used solid wooden boards, especially in medieval Europe where heavy oak covers protected manuscripts. Modern binding has moved almost entirely to pressed paper boards. The most common type is binder’s board, a dense pressed board also sold under names like Davey board, grey board, and millboard. Davey board is a high-density, single-ply board valued for its warp resistance and dimensional stability, and it is widely used in library binding and hardcover manufacturing.

Choosing the right board 🔗

Board selection depends on a few practical factors:

• Size and weight of the text block: Larger and heavier books need thicker boards to stay rigid and resist warping.
• Intended use: A book that will be handled daily needs a more durable board than one kept mainly for display.
• Conservation needs: Rare or valuable material demands acid-free, lignin-free board to prevent chemical breakdown over time.

Board grain also matters. Like paper, pressed board has a grain direction, and it bends more easily along one axis than the other. The grain of the board should run parallel to the spine so the cover flexes correctly when the book opens. For very large or thick covers, binders sometimes glue two boards together and press them overnight to build up the required thickness. Cheaper chipboard is generally avoided for larger books because it grows brittle and loses strength as it ages.

Cutting boards to a precise fit 🔗

Once the material is chosen, the boards must be cut to exact dimensions. A board is never cut to match the text block exactly. Instead, it is cut slightly larger so that it projects a little beyond the pages on three edges, creating a protective overhang. This overhang is called the square. The square typically extends a few millimetres beyond the head, fore-edge, and tail of the text block, shielding the page edges from damage.

The spine edge is treated differently. There the board is set back slightly from the text block to leave room for the hinge to flex, so the cover can swing open cleanly without straining the joint. Squares vary by tradition: fine binding often uses generous squares, while mass-produced books use smaller ones.

Accuracy is everything at this stage. Binders mark measurements in several places, check that corners sit at a true 90 degrees with a set square or T-square, and cut against a metal straight edge rather than a plastic one. A professional studio or library uses a board shear, a heavy guillotine-style cutter that produces perfectly square cuts with minimal effort. For hand cutting, the recommended technique is to make several light passes with a sharp knife rather than forcing the blade through in one stroke, which keeps the edge clean and square. A self-healing mat protects the work surface, and a fresh blade prevents ragged edges.

Attaching boards to the text block 🔗

With the boards cut, the next task is joining them securely to the sewn text block. In traditional craft binding, this is done by lacing-in, a method that has been the standard way of attaching boards for well over a thousand years.

Lacing cords through the boards 🔗

When a book is sewn, the sections are stitched onto supports that run across the spine, either cords or flat tapes. The loose ends of these supports, called slips, project from the spine. Lacing-in uses these slips to anchor the boards. The process, described in classic binding manuals, runs roughly as follows.

The board is placed against the spine in its correct position, level with the head, and the points where each slip meets the board are marked. Holes are then pierced through the board at these marks. The slips themselves are prepared by being frayed out, meaning the cord is teased apart into thinner strands so it lies flatter, then scraped, pasted, and tapered to a point so it can pass through the hole easily.

The slip is drawn tightly through the first hole, then brought back through a second hole nearby, locking it against the board. The traditional Zaehnsdorf manual recommends placing the holes about half an inch from the edge for an octavo volume, with the second hole roughly half an inch from the first. Once the cords are laced, the excess is cut off close to the board.

Why diagonal holing became standard 🔗

Early bindings often used holes drilled straight out from the spine in a line, but this weakened the board, particularly after paper boards replaced wooden ones. Binders shifted to diagonal holing, which spreads the strain and produces a stronger attachment. A further refinement, introduced toward the end of the eighteenth century, was to cut shallow channels into the board between the holes so the laced cord sits flush rather than proud of the surface. This grooving lets binders use thicker, stronger cords without the lacing showing through the cover.

After lacing, the cords are hammered flat against a hard surface. This closes up the holes, flattens the slips, and ensures no bump will show once the book is covered. Any projection left in the slips would be clearly visible through the finished leather or cloth, so careful, even hammering is essential.

Lacing with tapes 🔗

Many books are sewn on flat tapes rather than round cords, and the principle is the same. The tape ends are frayed out, the boards are punched with small holes, usually only two or three millimetres wide, and the tape ends are pushed through. As one binder describes the method, the board is held at 90 degrees to the book and right in the joint, the tape is pasted under the board, fanned out, and stuck down. The work is then left to dry under weight before the tapes are knocked down flat. A thin buffer such as acetate is often slipped between board and book to stop stray paste from sticking the wrong surfaces together.

In machine-made case bindings the logic is reversed: the cover, boards and all, is built separately and the finished text block is glued into it during a step called casing-in. But for hand binding and conservation work, lacing remains the strongest and most respected way to attach boards.

Gluing the spine 🔗

Gluing holds the whole structure together, and the choice of adhesive has a direct effect on how long a book lasts. The spine in particular needs an adhesive that bonds firmly but stays flexible, because a brittle spine glue cracks every time the book is opened.

Applying glue to the spine 🔗

The spine is glued by working a thin, even layer of flexible adhesive between the sections, taking care that it does not soak too deeply into the gutters where it would stiffen the pages. After this first gluing, a layer of mull, an open-weave cotton spine-lining cloth, is laid over the spine. The mull is cut wider than the spine so it extends a few centimetres on each side. These projecting flaps, sometimes called wings, later attach to the boards and reinforce the joint. A layer of kraft paper is often added over the mull for extra strength, and the spine is left to dry under light pressure to hold its shape.

Choosing the right adhesive 🔗

Several adhesives are used in binding, each with its own strengths:

• Wheat or rice starch paste: A traditional plant-based adhesive made by cooking starch with water. It dries flexible, is fully reversible, and is widely used in conservation and restoration for attaching endpapers and covering materials.
• Animal glue: Protein-based glues such as hide glue have been used for centuries on spines. They offer strong, flexible bonds and can be reactivated with heat and moisture, which is why binders recreating historical bindings often choose them. Purified animal glue, known as gelatine, is used in fine work and restoration.
• PVA (polyvinyl acetate): A modern synthetic adhesive that is strong, water-soluble, dries clear, and stays flexible. Conservation-grade PVA is acid-free and pH-neutral, making it suitable for archival work.
• Methylcellulose: A gentle, cellulose-based adhesive used for fragile papers or as a sizing agent. It is highly resistant to mould and can be mixed with other adhesives to adjust their properties.

For long-term preservation, the two qualities that matter most are flexibility when dry and a neutral pH. Conservation labs commonly rely on pH-neutral PVA such as Jade 403, which is acid-free and reversible with water. Ordinary craft glues like household white glue are avoided for valuable work because they can yellow and grow brittle, eventually cracking along the spine. In practice, many conservators blend adhesives, for instance mixing PVA with paste or methylcellulose, to balance strength, working time, and reversibility.

The importance of acid-free materials 🔗

The thread running through all three stages, from board to glue, is the avoidance of acidic materials. Acidic boards and adhesives release compounds over time that attack paper and leather, causing yellowing, brittleness, and decay. Using acid-free board, neutral paste, and pH-neutral PVA is the single most important factor in making a binding that survives. A book is only as durable as its weakest material, so a beautifully laced binding glued with a poor adhesive will still fail.

Taken together, these operations show why binding is treated as a precise craft rather than simple assembly. Cutting establishes the correct fit and protective squares, lacing creates a mechanical bond that distributes stress across the boards, and gluing seals the structure with a flexible, lasting hold. Each step depends on the one before it, and attention to material quality at every stage is what allows a bound volume to last for generations.

What do you think? If you were binding a book meant to survive a hundred years of library use, would you favour the mechanical security of traditional lacing or the speed of modern adhesive case binding? And how much should the choice of adhesive depend on whether a book is meant to be used daily or preserved untouched?

References

1. https://www.talasonline.com/Davey-Binders-Board
2. http://badgerandchirp.blogspot.com/2012/04/bookbinding-101-binder-board.html
3. https://cool.culturalheritage.org/don/dt/dt1978.html
4. http://papercutbindery.blogspot.com/2012/02/5-lacing-on-boards.html
5. https://www.schmedt.com/guides-tutorials/adhesive-glue-guide/
6. https://blog.papercraftpanda.com/know-the-difference-bookbinding-glue/
7. https://libanswers.dartmouth.edu/faq/29032