Jigoku hozo (hidden wedged tenon) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/jigoku-hozo-hidden-wedged-tenon/  (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).
- Jigoku hozo — "hell tenon": the wedge waits at the bottom of a blind mortise, and driving the tenon in spreads it into the flared mortise, so the joint can never be taken apart. Drawn in the assembled (spread) state.

dimension  value
stock  20 × 20 mm square
parts  mortised member, tenon member, wedge
mortise  10 mm at the face → 14 mm at the bottom, 15 mm deep
wedge  4 mm head, 12 mm long
assembles  wedge set in the tenon's kerf; driving the tenon home spreads it — it cannot come out
holds  pull-out, permanently

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/jigoku-hozo-hidden-wedged-tenon/index.json
API: https://xemstudio.com/api/geometry?object=jigoku-hozo-hidden-wedged-tenon