The victim. Another free book from the library. I checked more carefully this time to be more sure that it was a standard sewn binding in a standard case. It turned out to be just what it appeared.
Backed spine. 10 quires, the quires are visible as little "lumps" along the top edge of the block of pages inside the case. Each quire also has visible a very slight "gap" at its center, indicating where the gathering of sheets is folded.
You might think of a quire as a sort of comic book or pamphlet, of "sheets" which are laid atop one another (8 sheets in the case of this book) and then folded, to create (in this case) 16 leaves, or 32 pages. The book is 320 pages long, plus one tipped in plate which we will see later on.
Opening it up at the middle of a quire, we've going to find the stitching, to verify that we're looking at a sewn binding.
Here is the stitching. Note the black thread in the middle, yellow/plain linen elsewhere, which gives us a clue as to the details of the sewing. Evidently each "stitch" is sewn separately, in this sewing pattern. Again, we'll see a little more on this later. There are many patterns for sewing, however. When hand sewing, I usually use a single piece of thread for the entire binding, so you'd never see this sort of color change.
For comparison, this is what pages look like that are NOT the middle of a quire. No stitching visible! The outer pages of quires, where one quire meets the next, look slightly, subtly, different again. We''ll see this shortly.
Beginning the teardown, we'll cope with endpapers first. Here is the endpaper tipped on to the last page of the book. You can see the narrow band where the endpaper is glued to the outer page of the outermost quire.
We tear the tipped-in surface off, separating the text block, and then the endpaper is free for another 1/4 inch or so at the hinge, and then we peel it up from the pastedown a little. I am pretending that I want to preserve the endpapers here. Note the cheesecloth/mesh material of the mull now becoming visible.
Recall that the mull is glued to the spine of the text block, and then to the case. We can see here where the mull crosses the hinge area from text block to case.
Both endpapers de-tipped and peeled back, pastedowns area slightly lifted. If we wanted to rebuild the text block, replace the mull, and glue it back into the case (a reasonable thing to want to do, often) we'd need to lift more of the pastedown to expose more area on the case for regluing the new mull. This will do for illustration, however.
I'm just going to cut the mull to free the text block.
Text block freed, end papers more or less intact on the case. If i were to do the rebuild described above, I would lift the endpapers further without the text block in the way, and clean up the leftover mull glued onto the case to create a fresh area to glue new mull on to.
Preserving endpapers is a gigantic pain in the ass.
If you inscribe a book to someone, never, ever, write on the endpapers. You never know, the book might be important to someone, and they might want it repaired. The endpapers might not survive the repair, and your inscription would be lost.
Leaf in a page or two before you inscribe. Please!
Spine of the text block. Note spine inlay material, the brown paper. The method here is to build a laminate of paper and glue, over the mull, to create the right degree of stiffness in the spine. You want the spine to curve gently when the book is fully open, rather than bending and concentrating stress along a single line. The spine inlay also protects the case and the text block from one another, allowing them to move freely against one another without abrasion.
Spine inlay scraped off to reveal the mull. Stitching thread becomes visible, see the black lines across the spine? That's the black thread we saw inside the quire, at the center. We can roughly guess how the stitching works now.
Scraping/peeling the paper off with a knife up to this point. Next up, we'll use coarse sandpaper.
Another view of the mull, at the same stage of disassembly as above.
Sanded down to clean up, we're down to mull+glue at this point, and we're beginning to abrade the mull. There is very little stiffness left in the spine. The stitching is still intact under the mull.
Let's start taking the text block apart. We'll cut the quires one from the other, which will cut the stitching as we go.
The stitching serves two functions. The first is to "staple" the quires together in the sense that, say, a comic book or saddle-stapled pamphlet it stapled. The nested stack of pages is held together at the fold by the thread (and, as we shall see, sometimes a little glue). The stitching also connects each quire to its neighbors, however. So, cutting the quires apart cuts the threads and will, generally, have a side effect of disassembling the stacked pages of the quire. We'll see this shortly.
Since after sewing the spine of the text block is painted with glue, we get a little seepage of glue between the quires, which effectively "tips" the outer pages of neighboring quires together. Also, a little glue can seep through the thread holes (see below).
Find the gap between two quires, by counting pages carefully, and watching out for tipped in plates! Check and double-check. Look at the spine from above, and so on. Note the glue seepage that has "tipped" one quire to the next. It looks subtly different from the way pages within a quire open.
Peel the quires apart, much as we did the endpapers from the text block. Gently pressing and working the two glued faces apart. The can damage the outer sheet of the quire, but that's an easy repair, so let us not panic overmuch.
Peeling further to expose the mull, view from inside the book, we've separated the quires at this point and what's holding them together now is the glued-on mull material, and the stitching. We have fully "broken" the spine of the book at this point -- you may have noticed this happening through normal wear and tear in an older book. The cheesecloth of the mull is visible, if you peer closely.
We cut the quire off now, slicing the mull and quire-to-quire stitcthing. The quire, a separate 32 page booklet now, gets separated entirely. The stitching got cut, which will release the thread from its "stapling" duties to a degree.
Open the quire to the middle page, here is the stitching we noticed in the intact book, well above. It's starting to pop loose and can be (gently) pulled up and out.
Removed stitching, a clean spine. The quire still hangs together due to glue seepage through the thread holes and also, I think, the way the holes were punched.
Pulling the sheets of the quire apart. Note glue seepage through stitching holes, requiring a careful touch. Innermost sheet first, careful at the stitching holes, them gently apart to give the paper time to gently de-laminate and leave a glued face behind. Again., if you damage a sheet at this point, it's not a big deal, this is an easy repair.
The disassembled quire. 32 pages, 16 "leaves", 8 sheets of folded paper.
Note the plate tipped into the quire. This can throw your page counting off if you are careless. Check and double-check when identifying the ends of a quire! (the center has stitching and is easy to prove, the ends are a little more subtle). This quire appeared to have 17 leaves on one side, and 16 on the other.
Damaged outermost sheet of the quire, I did not do a very good job here. Also, if you get aggressive cleaning up the spine with sandpaper, damage may accrue here. This would need a repair (rice paper tape on the spine, re-punch stiching holes, very easy to do, and largely invisible once the book is rebuilt) if we were going to re-sew this.
And that's it! I could repeat the process with all the other quires, lift the pastedowns on the covers a bit more, and then I could re-sew the text block, rebuild the spine (new mull, new spine inlay) and glue the whole thing back into the case, and then re-glue the endpapers.