The part of a sewing support which extends beyond the width of the spine at either side and could be used to attach the boards or cover to a bookblock.
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.
Secondary tackets which attach a case-type cover to a sewing support.
Sewing supports that are placed on the outside of a case-type 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. On printed books this appears to be a northern European phenomenon, particularly France and the Low Countries, and the case is most often made from a relatively thick parchment (usually calf) without turn-ins, but sometimes with a fore-edge envelope flap.
Sewing supports made by laminating two or more layers of material together.
A sewing support made from a sheet material which has been folded one or more time.
Sewing supports in which the thread is wound around the supports rather than passing behind or across it.
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.
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.
A length of stiff or rigid material laid across one or more of the elements of a sewing support and sewn with it to reduce or remove the flexibility of the spine. The stiffeners will always be cut at the joints, as they cannot be used for board or cover attachment. Support stiffeners of copper alloy were recorded by Szirmai (Archaeology, pp 310-311) on printed books of the first half of the sixteenth century from Westphalia, but the use of stiffeners, including those made of wood, appears to have been a more general medieval archival practice.