Category Archives: bookbinding

A Guide to Swell

In bookbinding, the term “swell” describes the thicker area of a book block at the spine due to the addition of sewing thread. It depends on factors detailed below, but a binder or conservator generally does not have control over all these variables. Knowing how to estimate the amount of swell that will develop is one of the most important aspects when planning to sew a book, since it corrolates to the degree of round and the shape of the shoulders that a book will end up with.

Different binding styles need different amounts of swell. Too much swell creates a textblock that is unstable, squiggly, and difficult to back. Too little swell and there are insufficent shoulders which are necessary for some styles of binding. In all case binding structures, there is more leeway with amount of swell, and as long as it is not excessive it will be sucessful; with bound books the tolerances are much tighter. For example, if you are resewing an existing text block it is critical the new shoulders exactly fit the original boards.

Softer, multi-ply threads afford much more control of swell while sewing as compared to a hard modern thread. Currently, I primarily use threads sold by Colophon Book Arts, including the Colophon Best Blake Thread and the Londonderry Linen Lacing Cord #4. Both can be deplyed if desired to make them thinner. I also prefer to support smaller, specialist bookbinding supply companies. If you are using standard threads, 25/3  is a reasonable starting place. 

Many early binding structures—even up to the late 18th century—manipulate the shape of the boards to fit the spine, rather than the modern fine binding tendency to fit the boards to a 90 degree shoulder.  This makes it easier to fit a wider range of boards to a given swell. Obviously, this is not an option for many binding structures.

There is no formula, instead these ten aspects need to be considered:

1. THICKNESS OF THREAD. Thick thread (or more plys) = more swell. Thin thread (or fewer plys) = less swell. Although not ideal, the thickness of thread can be changed during sewing if too much or too little swell develops. 

2. HOW HARD OR SOFT THE THREAD IS. Hard thread does not flatten in the signatures = more swell. Soft thread flattens in the signatures = less swell. A compressible thread gives more control. It is often advisable to untwist hard modern threads a bit to make them softer by running them through your fingernail and thumb, and let them relax.  Waxing thread also makes it harder, so I generally avoid it if possible. Sometimes excessive kinking and twisting comes from using too small of a needle. Softer thread can fray more during sewing, though. 

3. THICKNESS OF THE TEXT PAPER. Thick paper absorbs more thread = less swell. Thin paper absorbs less thread = more swell.

4. HOW HARD OF SOFT THE PAPER IS. Soft paper absorbs more of the thread = less swell. Hard paper absorbs less thread = more swell. It is easier to control swell with softer paper. Guarding the spine will increase swell. Washing and resizing can also affect how much swell develops. Swell can also be adjusted before sewing by beating or otherwise compressing the sections.

5. HOW MANY LEAVES ARE IN EACH SIGNATURE. More leaves can absorb more thread = less swell. Fewer leaves = more swell.

6. HOW MANY SIGNATURES THERE ARE. More signatures = more swell. Fewer signatures = less swell. Some binders like to visualize this by wrapping the thread around a pencil the same number of times as there are signatures.

7. SEWING STYLE. All-along, two-on, three-on, etc. All-along produces the most swell, more “-on” sewing styles = less swell. Packed sewing produces more swell due to a small overlap of thread. This can be controlled, to produce naturally packed sewing, which has one length of thread on the cords for each signature.

8. SEWING SUPPORTS. Tapes, cords, thongs. Tapes produce the least swell, cords and thongs slightly more since the thread can overlap slightly inside the signature. Supports also differ in the amount of adjustment that can be done after sewing, ie. how much the thread can move on the supports during consolidation and backing. A professional sewing frame, such as the Nokey makes this easier.

9. HOW MUCH CONSOLIDATION IS PERFORMED DURING SEWING. More consolidation during sewing= less swell. I have often observed students sewing identical text blocks, with identical thread, end up with significantly different results. A loaded stick, or knocking down stick can help with compression, although some people prefer to use a bone folder or wedge shaped piece of wood.

10. TIGHTNESS OF SEWING. Tighter sewing makes a thinner book before pressing. Looser sewing can develop due to improper tensioning or too large of a needle. A book sewn too tightly can develop a “banana” shape, thinner at the kettle stitch. Even tension is crucial.

Best practice: sew with the thickest thread possible.

News from 1886: Hand Bookbinding is Slowly Disappearing

“Bookbinding on a small scale seems to be one of those minor industries which are slowly disappearing. Yet we think that there is always a certain need of a good bookbinder in every country town. We recollect how such a person was once maintained in a small European city by official work, and now and then a few orders from the country gentlemen. Shopkeepers and farmers as a general rule are not bibliophilists. When, however, we come in this country to look upon a book as something of intrinsic value, we will insist on real books, in proper shape and goodly binding, and then the bookbinder’s day will have come.”

The Bookmaker: A Journal of Technical Art and Information, January 1886, p. 16.


Weights of Litho Stones


G. Ruse and C. Straker. Printing and its Accessories. London: S. Straker & Son., 1860. Robertson Davies Library, Massey College. University of Toronto.

This is a pretty handy chart if you are considering purchasing a litho stone, or even picking one up to move around.  For example, a 16 x 12 inch stone weights 43 pounds per inch of thickness. This was pasted onto the inner face of the front board of Printing and its Accessories from Massy College.  Another reminder that many printed books contain unique, owner added paratextual information.

Book Slate

Nelson’s School Series Book Slate for Home and Student Use (London & Edinburgh: T. Nelson and Sons, [1900?]) is an odd structure, a diptych in a case binding. The exterior looks like a standard quarter cloth case binding with printed paper sides. The interior, however, is made from a painted slate-like material. It can be written on and erased. The earliest known diptych is from 14th-century BCE, making the codex seem like a newbie.  Is the laptop a 20th century iteration? Long live the diptych!

book slate

Nelson’s Book Slate. Exterior front board. This is a well used, but largely intact book. My Collection.

book slate 2

Nelson’s Book Slate. Open. Chalk marks of addition and subtraction. My Collection.

On Rushing



Rushing is an insidious demon in craft work. Its lures are many. It occludes the memory of its last appearence, trapping you once again. Resist with constant vigilance!

The Importance of Extra Binding

“I pity those who call themselves cultured and with fine art taste who cannot take from their shelves some few specimens of first-class modern extra binding … giving to their possessors every time they handle them finer feelings and sweeter ecstasy of pleasure than many more costly objects of art they possess.”

-William Matthews Modern Bookbinding Practically Considered. New York: The Grolier Club, 1889. (pp. 94-95)

PM-V11 Spokeshave Blade for Leather

Modified 151 spokeshaves are used by bookbinders and leather workers for reducing large areas of the thickness of leather and are especially good at creating a long gradual bevel. They are also indispensable for working calf, which is difficult to pare using a Scharf-Fix machine. I’ve been experimenting with the somewhat new Lee Valley PM-V11 spokeshave blade. PM-V11 is a proprietary steel designed for woodworkers, and reportedly has the ease of sharpening of 01 steel and the durability of A2.

I’m glad they did some testing of O1, A2 and PM-V111 metals, but have some problems with their methodologies. Most importantly, the assigning of a 0-10 rating for wear based on subjective visual examination, rather than the industry standard CATRA testing machine. Then a deceptive XYZ plotting of wear testing, impact resistance, and ease of sharpening all together creating a three-dimensional triangle. Where is Edwin Tufte when you need him?  They have developed a clever method of quantifying ease of sharpening, however. Oddly, at the bottom of The PM-V11 story page, they negate the need for testing, and lay on some aw-shucks folk wisdom, claiming that woodworkers don’t need an advanced degree in metallurgy or a scanning electron microscope to realize PM-V11 is a better blade.

In any event, I was still curious.  In order to work effectively on leather, first I reground the blade to 20 degrees using a 2 x 72″ belt grinder. Then I hand sharpened an A2 and PM-V11 blade side-by-side. There wasn’t much difference in the time it took. The PM-V11 blade did feel a little gummy, which some woodworkers speculate may be due to vanadium in the blade. Edge retention seemed quite similar, though possibly the PM-V11 lasted a bit longer. PM-V11 did seem to have slightly better initial cutting performance (sharpness), however. Most importantly, PM-V11 was quicker to strop back into action than A2; it felt more like an M3 steel.

Even though PM-V11 and A2 don’t seem to be massively different, I will continue to experiment. Both of these steels are excellent. Yet, concentrating on subtle differences can reinvigorate interest in repetitive handwork, helping to stave off the inevitable boredom which looms at the edges of all professional craft work. Or, put another way, buy more tools.

Information about the history of 151 spokeshaves. At the end of this post there are tips on how to modify and use them for leather work.

Or you can purchase a already modified 151 spokeshave and blade for leather.


Note the thinness of this leather shaving from a 151 spokeshave and PM-V11 blade. Spokeshaving should produce shavings, not dust.


A display of very regular shaving morphology. A sign of a sharp blade that stays sharp.