One of the reasons I started the Bible Design and Binding Blog was to serve as a clearing house for information. Over the years, I've corresponded with a lot of people who share my interests, and I've learned a lot from them. I hope this blog will become a community where that kind of information exchange thrives. A perfect example from over the weekend is Dave's comment on glued and sewn bindings, which states the differences much more clearly than I've managed to do. I want to reproduce it here as a guide to others, along with an invitation to add what you know in the comments:
I freely admit that I also don't know much about the sewing methods, but there are a few varieties that I've run across in my searchfor the "perfect" Bible. The first is the typical glue binding where the end of the signatures are cut flat (usually with some grooves cut into them transversly to help the glue hold), pressed together, and glued.
The second is what I call the "hybrid" glue binding, where the individual signatures are sewn in the middle, so if you open the Bible and find the middle of the signature, you can usually see the threads if you pull it open far enough. These signatures are then pressed together and guled like the completely glued bindings. I believe they also cut grooves transversly into these as well. The advantage of this is that you are less likely to have individual pages come unglued, but if you open the binding too far, you can get the whole signature to come out. You can usually tell these from the normal, fully sewn bindings if you look at the edge of the spine. Ther you will see the sewn signatures, but there will be glue holding them together. If you open the book, usually the signature will be so tightly pressed together and held by the glue that they will stay in a straight line.
Finally, the fully sewn bindings have sewn signatures like the ones above, but they have strips of fabric holding the signatures together. I believe on the really nice Bibles, these are sewn to the signatures somehow and on the lesser nice ones, they are glued to the signatures. Either way, these will let the book open flat, and if you look at the edge of the spine with the book open, they will usually leave a gap between the spine cove and the text block, since they are not tightly pressed and glued together. Crossway's journaling Bible, as near as I can tell, is of the type that has the sewn signatures with the fabric strips glued to them.
After reading Dave's description, I wonder if some of the bindings I've been calling sewn because of the visible stitching are actually the glued/sewn hybrids he's observed. Thanks, Dave, for sharing your observations. As always, the floor is open to anyone who can fill in more details ...