A bone folder is a tool used to fold, crease, and score paper. For book and paper artists alike, a bone folder may be considered their right hand. Typically a bone folder is made from the leg bone of a cow, deer, or elk. Synthetic bone folders are available, made from plastic and Teflon. (http://www.valleyridgeartstudio.com/bone_folders/)
I have had both a plastic and a Teflon bone folder, and I much prefer the Teflon. It is heavier and feels more substantial in my hand. It is virtually indestructible and can be used for all kinds of projects because it does not burnish, or make shiny, the surfaces it is used on. Teflon is also non-stick – an important quality when you’re working so often with strong glues.
My plastic bone folder was flimsy, and the tip of it eventually wore down to a dull edge rather than its original point. I often felt like I was going to snap it in half.
I have never owned a bone folder actually made of bone, so I can’t give my opinion on those, but I would wholeheartedly recommend investing in a Teflon bone folder if you’re a serious book maker or crafter. It really is an indispensable tool, and the higher price is worth every penny. My Teflon bone folder doesn’t have a pointy enough end to use for scoring, but that’s what spoons are for.
A good bone folder is an important tool in bookbinding, so choose carefully. There are gads of different sizes and shapes so if you only plan on buying one, I recommend a rectangular shape with one pointy end and one slanted end. Happy bone folding!