In this second method of rebacking a hardcover book, the new book cloth is under the original bbok cloth and the turn-ins are under the endpapers. The new spine is constructed on the book with the turn-ins glued under the end papers. When the original spine is replaced, the new book cloth shows in only a small portion of the joint area.

Measuring the Text Block Spine

Use a strip of paper to measure the width of the text block spine (measurement A), then add 1 – 2” to each side of the spine measurement marks.
The exact amount added to measurement A depends on how much of the
original book cloth is trimmed away from the cover board. It’s better to have
this measurement too wide as any excess can be trimmed away later.
Use the same technique to measure the height of the book boards (measurement B) then add 1” to measurement B.

rebacking a book