If you work with paper, you need a bone folder. This set of 3 from the Felt & Wire Shop will only set you back $15 and proceeds benefit the not-for-profit WNY Book Arts Center.
A Bone folder is possibly the most essential tool for a paper or book artist.
When using the bone folder: Hold it in a loosely gripped fist, with fingernails lightly resting on the table and the bone folder resting on your fingertips. Your thumb should be on the opposite side of the bone folder. Apply a downward pressure with your thumb, and your fingernails will drag along the table surface next to the edge of the paper. The tapered end of the bone folder should be applied to the edge of the paper. Don’t dig into the paper, use the flat side to compress the fold.
Folding bones help fold, crease, and score paper. They are traditionally made from cow, deer, or elk bone. Today, most commercially-available ones are made of plastic, Teflon, or wood. The best are still made of real bone.