Butterfly key (bow-tie, dutchman) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/butterfly-key-joint/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design — geometry computed in the generator from traditional proportions
Catalog version: 2026-10-20

Overall (mm): length 80.0, width 80.0, height 20.0
- Woodworking joint drawn for 3D printing: the parts lock together by shape, so a print can be joined without glue or screws. Drawn at true size with the parts line to line (zero gap) in their assembled position — add your printer's fit allowance to the mating faces (your AI or slicer can do this).
- A bow-tie shaped key let into the surface across a joint or a crack.

dimension  value
stock  20 mm boards edge to edge
parts  board a, board b, key
key  40 long, 16 at the ends, 8 at the waist, 8 mm deep
assembles  boards together, key pressed in from above
holds  the two boards (or a crack) from pulling apart

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Xem Studio: Joinery design (geometry computed in the generator from traditional proportions) — web — Xem Studio design — https://xemstudio.com/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 4 parts): https://xemstudio.com/files/hardware/butterfly-key-joint/index.json
API: https://xemstudio.com/api/geometry?object=butterfly-key-joint