Watched my local bindery switch from hand sewing to a machine in 2019, and the spines just are not the same
There is a shop over in Portland that I used to visit for repairs, and back in 2019 they brought in a Smyth sewing machine to replace three people who sewed signatures by hand. The books come out faster now and cheaper, but the spines do not open as flat and I have had two of their rebinds crack near the hinge after about a year. I still take my grandfather's old volumes to the lady who works out of her garage and sews every signature herself. Has anyone else noticed machine-sewn spines holding up worse over time, or is it just the glue they use now?
Tbh the part about spines not opening as flat rings true for me. I read a piece from a bookbinder in Vermont who said Smyth machines tend to punch the holes closer to the fold than a hand sewer would, which limits how far the pages can flex before the paper starts to tear. That matches what you saw with those rebinds cracking near the hinge after a year. The glue thing gets blamed a lot but the sewing itself sets the spine up to fail or hold.