How to Make Clam Shell Book Boxes

A simple corrugated clam shell box can be constructed from a sheet of single wall acid-free corrugated board. These boxes are faster to construct and cheaper than the traditional clam shell box seen in many libraries.

The design for this corrugated box was developed by Andrea Krupp and Lillian Greenberg of the Library Company of Philadelphia and originally printed in The Abbey Newsletter, October 1991. Further refinements on the instructions are provided by the staff of the American Philosophical Society. Like a clam shell from which it derives its name, the corrugated box has a book tray constructed to fit the box and a cover tray that fits over the book tray.
Constructing a Measuring Jig
1. Cut 3 strips of the corrugated board about 12” long.
2. Trim 1 strip to 9” long and trim 1 strip to 6” long.
3. Glue all 3 strips together with one end even. The other ends will be stepped.
4. Mark the longest strip 1 BT (board thickness). Mark the middle strip 2 BT and the shortest strip 3 BT.
Measure the Book
5. Using a piece of paper, measure the book height (A), width (B) and thickness (C).
NOTE: Not all books are square. Be sure to measure the tallest, widest and thickest part of the book.

Transfer the Measurements and Rough Cut the Corrugated Board
NOTE: The corrugations of the board run parallel to the height of the book.
6. Square a piece of corrugated board on a paper cutter or using a carpenters’ square. Mark the square corner with an “X”.
7. Starting at the squared comer and working to the left, mark 2 widths (B), plus 3 thickness (C) plus about 2”.
8. Again starting at the squared corner and working upward, mark 1 height (A) plus 2 thickness (C) plus 2”.
9. Cut the board to size with a paper cutter or sharp utility knife.
Laying Out Cutting and Folding Lines
Vertical Measurements
10. Starting at the bottom left hand corner, mark 1 thickness (C) plus 1 BT. This is the thickness of the cover tray wall.
11. Add the width of the book (B) plus 2 BT. This is the width of the cover tray base.
12. Add the thickness of the book (C) plus 2 BT. This is the thickness of the spine.
13. Add the width of the book (B) plus 1 BT. This is the width of the book tray base.
14. Add the thickness of the book (C) plus 1 BT to mark the thickness of the book tray wall.
15. Draw lines using a triangle or carpenters square. Trim off excess board.
Horizontal Measurement
16. Starting at the bottom left hand corner, mark the thickness of the book (C) plus 1 BT. This is the thickness of the cover tray wall.
17. Add the height of the book (B) plus 3 BT to mark the height of the cover tray base.
18. Add the thickness of the book (C) plus 1 BT. This is the thickness of the cover tray wall.
19. Draw lines using a triangle or carpenters square. Trim off excess board.
Decreasing Book Tray and Cutting Excess
The book tray must be smaller than the cover tray so the two trays will nest inside one another  when the box is closed.
20. Use the BT measuring jig to move the upper and lower book tray walls inward by 1 BT.
21. Draw diagonal lines from the outer comers of the tray bases to the corners of the walls.
22. Cut away the shaded areas with a knife.
Note: Extend the cuts in the new shortened book tray base lines.
23. Round the comers of the cover tray top and bottom walls and cut a thumb notch on the cover tray fore edge wall. Use a gouge and mallet or scissors.

Folding and Creasing Box Lines
24. Using the rounded end of a folder, score all of the fold lines lightly.
25. Lay a ruler along the scored lines and fold the cardboard against the ruler. Use the
folder to sharpen the folds.
Cutting and Attaching the Tabs
The corrugated board is constructed of two outer layers surrounding a layer of corrugated core.
26. Using the pointed end of a folder, separate the two outer layer from the corrugated core.
27. Fold the outer layers back on the scored line. Use scissors to carefully cut away the corrugated core. Do not cut through the corrugated core.
Gluing the Corner Tabs to Construct the Box
28. Use PVA to glue the corner tabs in place. Push the inner tabs well down into the corner joints.
29. Use clips to hold the tabs in place while they dry.
30. Label the spine, place the book in the box and on your shelf.