Hammer time! Gluing, rounding, and backing our books

The spine of a book is the part which takes most of the punishment and a number of techniques have developed over the centuries to keep the thing in one piece. Modern books — even most hardbacks — are made of single sheets held together at the spine with a hot-melt glue in a method called “Perfect Binding”. Even when the books are stitched, they’re usually backed with a thick layer of rubbery, modern glue.

This is the spine of a Bible that I’ve disbinded for recovering and you can see the multiple rows of machine stitches and the remaining sheen of the glue that I’ve removed with great difficulty and not a little elbow grease.


This Bible was bound in the 1960s so it was still relying mostly on that stitching with a secondary reliance on the glue. There are actual signatures and it’s made in a manner not all that dissimilar to what we’re doing here, just with mechanized assistance. But still, the text block is hanging on with stitches and glue.

The sort of gothic binding we’re dealing with, is a flexible binding, held together by the cords and headbands. (Okay, also a thick layer of gooey, old-school… um… glue, but this glue is made collagen instead of petroleum. I’ll take that trade any day, but we’ll talk about glue later.)

The guide board with a trimmed book block atop it, plough in the background

Once we have our book sewn onto the cords and the three faces are trimmed, it’s starting to look like a proper book. To prepare it for the next phase, when we will lace it onto boards and cover it in leather, we want to shape and create the spine which will allows this sort of flexible binding to hold together through centuries of grubby-handed readers.

First, we’re going to form the spine, because without a correctly-formed hinge, our book will fall apart like our 1960s Bible did, after a mere five decades of handling. For that, we turn to the two steps of forming the spine of our book: rounding and backing.

Step One: Rounding

Rounding is the forming of that nice, arched, shape that’s lovely to feel, but also gives the book the room it needs to open fully and flat, inverting the curve and reducing the stresses on the stitching.

In modern case binding, like we see in the Bible above, instead of stitching to cords or tapes, binders will run lines of kettle stitch (we used kettle stitches at the head and tail of our book, if you recall) and forego the cords altogether. In part, this is possible because moderns can lean more heavily on the strength and perpetual flexibility of their glues.

Another reason to round is that it’s prelude to backing, which will help us accomodate the fact that the folds and the thickness of our thread makes the spine thicker than the edges. But we’ll get to that next.

A large English pattern shoemaker or bookbinder's hammer
English pattern shoemakers/bookbinding hammer from my collection.

BTW: This is when we get to use our hammer. If you don’t have a bookbinder’s or shoemaker’s hammer, you can substitute a standard framing hammer for rounding and use a piece of wood between the hammer and the spine of your book for the backing step.

To round:

  1. “Jog” the book one last time, by dropping it lightly on your bench top to square the edges and then pinch to hold it in that square state.
  2. Still applying pressure to hold that square, place the book flat on a hard surface (traditionally marble or a lithographer’s stone, but your benchtop will suffice) and use your fingers to push the center of the page edges toward the spine. This will form an gentle arch in the spine. Hold this in place.
  3. Use the face of your hammer to lightly persuade the book to accept and keep the arch. What you’re striving for is to use the force of these light, glancing taps of the hammer to move the stitches ever-so-slightly along the cords, which will help hold your desired shape.


As I mentioned earlier, this is the part when we are trying to accomplish two things: accomodating the slight swell of the spine caused by folding paper and laying thread in the folds, and also accomodating the thickness of the boards to form a durable hinge and allow the full flex of the spine, allowing the open book to lay flat*, should you desire.

This is more art than science and requires significantly more practice than I’ve currently put into it, but here’s the general idea and more resources and videos are linked in the resources section below.


  1. Clamp your text block into a sturdy frame, spine up, with a pair of backing boards. Backing boards have a beveled top which is often metal reinforced, I made mine out of plywood. The bottom of the backing board is usually narrower than the top, forming a shallow wedge, which pinches the book by directing the force of the press toward compressing the book at the spine.
  2. Apply a light layer of a flexible glue such as hide glue or a starch glue (you can use PVA glue if you don’t care about 16th century accuracy and just want a quick sketchbook or something.) Use your brush or fingers to make sure the glue gets into the crevices a bit, bonding the signatures one to the other.
  3. Let the glue dry thoroughly before continuing. It’s a good time to pet the cat, play with the dog, put your feet up and read a book… just leave it alone for a bit and come back to it.
  4. Okay, we’re ready to start backing. You’ll want to practice this one before doing anything precious. Here’s why bookbinding hammers are usually so heavy. Holding the hammer lightly, up near the head of the hammer, practice picking it up and letting it fall (without letting go, of course). You’re not swinging the hammer like you would driving a nail, you’re using just the weight of the hammer, letting it fall while your hand guides it, pulling it toward you to make a glancing blow to the spine of the book. What you’re trying to do is shape the book spine into a sort of mushroom shape.
    If you don’t have a backing or cobbler’s hammer, you’ll need to distribute the force a bit to mimic what you’d get from the broad face of the “proper” hammer. Place a small block of dense hardwood between the hammer and the spine.
  5. What I’m doing wrong in the video below: I shot some quick video to demonstrate the technique, and realized after the fact that I was paying too much attention to recording and not where the hammer was falling. When you’re doing this, stay away from the cords. Flattening the cords is my mistake, but I can re-raise them using a piece of hardwood and delicate blows to reshape them. This will be important when we’re putting the leather on.

I’m going to put off glue until next time. It will be one of the most important things to understand before we start laying leather down and it deserves a full discussion of what it is and how it’s made.

More later,


Please note: Though our construction methods allow for fully-opening or lying flat, it’s a bad idea to do so with a genuine antiquarian book or incunable. Rare books should always be handled in a manner consistent with best practices followed by conservators and the institutions where they are archived. 

Book conservators go to great lengths to keep from stressing the spines, but, of course, we’re talking about the difference between something we bound yesterday versus something bound in a monastery 500 years ago, so… yeah. FYI

Further reading & viewing on bookbinding (mostly modern)

Sea Lemon, Videos by a modern binder/video blogger on YouTube. Well thought-out and clearly demonstrated, Jennifer at Sea Lemon does a good job of grounding her tutorials in the DIY space and doesn’t assume you have a workshop full of specialized bookbinding tools and presses.

The Center for Book Arts: The CBA in New York City is really the national (US) go-to for bookbinding information and tips.

iBookbinding,com is a the brainchild of Russian bookbinder Stepan Chizhov, now living in the Netherlands, filled with articles and research. The approach is modern and he uses 3D printing quite a bit to make tools. Some really interesting stuff.

Late edit to add some more videos

This video is Angela Sutton, a bookbinder’s channel with some good detail in her videos, including reshaping and re-positioning the cords during backing.

MHR is the pseudonym of an American bookbinder who has put up a treasure trove of articles on the craft and artful, supporting videos for her work.

One comment

  1. I didn’t know that you could use a hammer in binding. My wife and I want to rebind some old home projects we were working on. We’ll have to order the right glue.


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