Hole spacing of four-hole thread-bound books

13 to18mm. Because the double-hole thread-bound book has two standard paper pinholes, the upper and lower positions are one-third of the book length and 6 to 9 mm away from the spine; Generally, there are four pinholes, which refer to the standard of two-hole thread-bound book, so the hole distance of four-hole thread-bound book depends on the sewing form, and the distance from the spine is13 ~18 mm.