Bone Folder
A polished, tapered bone used to crease, burnish and rub down a fold or a pasted sheet.
| Length | 150–200 mm |
| Material | Cattle bone, or Teflon |
| Profile | Tapered to a rounded, polished point |
| Edge | Rounded, never sharp |
| Weight | 40–70 g |
| Finish | Polished with fine abrasive, then burnished |
| Care | Wipe clean; never soak |
| Lifespan | Decades with care |
| Length | 150–200 mm |
| Material | Bone or Teflon |
| Suitable stock | All papers and boards |
| Processes | Creasing, burnishing, rubbing down, opening sections |
| Compatible materials | All papers, PVA, starch paste |
| Pressure | Firm but even; the folder should slide, not scrub |
| Cleaning | Teflon: solvent. Bone: dry cloth only |
| Minimum radius | Will not crease board above 300 gsm without a score |
There is a simulator for this. Bindery Simulator runs the same relationships in 3D, so you can change a number and watch what it does to the result.
The bone folder is the tool you reach for more than any other on a binding bench. It creases a fold, it burnishes a pasted-down endpaper, it rubs a paper joint into a spine, and it opens the sections of a book so they can be sewn. It is a piece of bone, tapered to a rounded point, polished so it slides rather than drags.
Teflon folders are the modern alternative. They do not leave the faint sheen that bone leaves on coated stock, and they can be cleaned with solvent. Bone is still preferred for genuine paper, where the slight burnish is wanted.
Safety
Using it well
- Rub the folder on a scrap of waste paper first. A new folder has a surface that marks the first sheet it touches.
- For a crisp fold, crease with the folder over a hard surface, then burnish the fold again with the sheet folded. Two passes give a much sharper result than one.
- Keep one folder for clean paper and one for pasted work. Paste picks up grit, and grit scratches the next sheet.
What it works with
Papers and substrates
- All papers, up to about 300 gsm without scoring
Type and fonts
- Not applicable
Processes
- Creasing
- Burnishing
- Rubbing down
- Opening sections
- Marbling
Tools that go with the bone folder
Paper Cutter
A guillotine or a board shear: the tool that trims a text block square and a sheet to size.
Bookbinding Glue
PVA for strength, starch paste for reversibility, and the mix that does both.
Endpapers
The folded sheet that joins the text block to the cover, and hides the join.