Estimating the thickness of the spine

Note that the length and size of a cover sheet depends on the thickness of the book block spine.

The following list shows examples for A4 size or 8¹/₂" × 11", 80 g/m² (20 lb. Bond) paper:

• 10-sheet book block: 1 mm (0.04 inches)

• 30-sheet book block: 3 mm (0.12 inches)

• 50-sheet book block: 5 mm (0.20 inches)

• 80-sheet book block: 8 mm (0.32 inches)

• 100-sheet book block: 10 mm (0.40 inches)

• 200-sheet book block: 20 mm (0.80 inches)

Specify the cover sheet size based on the thickness of the book block spine. Use the following equation to calculate the length of the cover sheet:

Minimum length of cover sheet (mm/inch) = "length of book block sheet (mm/inch)" × 2 + "thickness of spine (mm/inch)"

To perfect bind a booklet with the following dimensions, specify a cover sheet length of at least 440 mm (17.4 inches):

• 200-sheet book block: A4 or 8¹/₂" × 11"

• Spine thickness: 20 mm (0.8 inches)