Bookbinding Tools
Lay out a book cover with spacers and corner guides
Three measurements shape the case. Board thickness affects the material that turns around the edge. Hinge spacing determines the gap beside the spine. The cutting offset at a corner leaves material to wrap the board.
Find out what each number measures
A number on a guide can refer to the gap between boards, the width of the ruler or the distance from the corner to the cut. Check the instructions for that piece and keep these dimensions separate. A spacer that repeats a hinge gap may serve no role in determining the cut.
Test how the turn-in meets at the corner
Use an offcut of the actual board and covering material. Fold the test turn-ins over the edges and inspect how the corner closes. Add the test to your measurements if you change board thickness or switch from paper to a thicker cloth.
Repeat the layout with a dry fit
Position the spine and both cover boards with the guide, then check the spacing against the book block before applying glue. A set with an L ruler and a spacer lets you set a margin and a gap independently. Check the offered sizes against your own layout.