Does anyone know what adjustment can be made on a National Booksewing machine to make the stitching tighter? Right now my stitching is really loose, with loose loops on the outside of the spine and some slack on the stitches on the inside of the signatures. There are so many adjustments that can be made on this machine, and I've tried adjusting most of them, to no avail. This is an old machine, but I guess I'm hoping somebody out there still runs one.
