BowSpan - Flat Ribbon Bow Forks | 40, 60 & 80 mm

BowSpan is a set of three flat, open-ended forks for arranging ribbon loops and tying their centre with a separate narrow ribbon or cord. The long handle keeps the working area clear, and the open slot provides access to the centre of the loops.

Sizes

Choose 40, 60 or 80 mm nominal outside fork width. All three tools are 108 mm long, with a 4 mm body and a 0.4 mm raised size label on the handle. The central slot is 8 mm wide with a rounded bottom; the storage hole is 6 mm in diameter. The numbers describe the tool, not the exact finished bow width.

How to use

1. Smooth any rough print edges that will touch the ribbon. Hold the handle with the open tips pointing upward.

2. Leave a ribbon tail and wrap one or more loose, even loops around both prongs. Keep the loops on the straight working area and leave room above and below them in the central slot.

3. Pass one end of a separate narrow ribbon or cord from front to back through the central slot below the ribbon bundle. Run it behind all the rear layers, then return it to the front through the slot above the bundle. Tie the two ends loosely at the front. The entire tie must surround both front and rear layers, with both prongs outside it.

4. Slide the loops upward off the open tips, then tighten the centre tie and arrange the loops and tails by hand. Start with a narrow, inexpensive ribbon sample to check friction and the result.

Printing

Print the flat underside on the bed, with the size label upward. Suggested starting point: PLA, 0.4 mm nozzle, 0.2 mm layers, 3 perimeters and 15% infill. The geometry is designed without supports. Use a suitable printer and material profile, inspect the sliced preview, and check the contact edges before use. No printer-specific G-code is supplied.

Verification status

The three exported STL files and three geometry-only 3MF files were independently checked for a closed single body, dimensions, slot and hole openings, attached size labels and correct 3MF placement. All six exports produced actual toolpaths with an isolated generic PLA slicing profile, including the raised size numbers.

Physical printing and use with real ribbon have not yet been tested. Ribbon compatibility, edge finish, strength, knot retention and finished bow dimensions remain unverified. The illustrations are CAD renders/projections of the exported models and a schematic ribbon path, not photographs of a tested print.

Files

Three STL files and three geometry-only 3MF files in millimetres, original parametric Python source, bilingual instructions and licence. Choose one size or print the set; the variants belong to the same project.

Original CAD design by MARGRAF ITALY. Creative Commons Attribution 4.0 International. Fork-based bow making is an established crafting method.

Italiano

Tre dime piatte a forcella da 40, 60 e 80 mm di larghezza esterna, lunghe 108 mm. Avvolgere il nastro attorno alle due punte, lasciando libera la fessura centrale sopra e sotto il fascio. Con un secondo nastrino o cordino, passare un'estremita dal davanti al dietro attraverso la fessura sotto il fascio; portarla dietro tutti gli strati posteriori e riportarla davanti attraverso la fessura sopra il fascio. Annodare davanti senza stringere del tutto: l'intera legatura deve circondare gli strati anteriori e posteriori, lasciando entrambe le punte all'esterno. Sfilare verso le punte aperte e poi serrare il nodo. Il dettaglio laterale in galleria mostra il percorso prima di raccogliere il centro. Stampare il lato piano sul piatto, con il numero rivolto verso l alto, e levigare eventuali asperita. Le quote indicano la dima, non la larghezza esatta del fiocco. Prova fisica e uso con nastri reali ancora da eseguire.