Components placed across the spine of a bookblock to or through which the individual gatherings are sewn with thread. The most commonly encountered sewing supports are narrow strips of material around or across which the thread is taken when it emerges from the gatherings, but there are also pierced sewing supports, through which the thread is taken when the bookblock is sewn. Both can be found in many different shapes and sizes.
Lengths of material (cord, tanned skin, alum-tawed skin, etc.) glued into recesses cut across the spine of a bookblock.
Structures in which gatherings are sewn through the fold to either sewing supports or pierced sewing supports, as opposed to unsupported sewing structures that do not have any type of sewing support.
Sewing supports that are placed on the outside of a case-cover, which is therefore also sewn through as the book is sewn. Both sewing supports and pierced sewing supports can be found in this position.
Sewing supports in which the thread is wound around the supports rather than passing behind or across it.
Sewing gatherings through the fold to either transverse or pierced sewing supports, as opposed to unsupported sewing that does not have any type of sewing support.
A triple support has three elements lying side by side and, in the single example recorded on a late 15th-century German binding, was made from alum-tawed strap-type supports with two knife-cut across the spine.
Sewing supports which consist of three elements of a suitable material lying side by side across the spine of a bookblock.
Sewing supports made from all the most common core materials (parchment, leather, alum-tawed skin and paper) can be found rolled, a technique which had the advantage of allowing the thickness of the support to be easily controlled.
Secondary tackets which attach a case-type cover to a sewing support.