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Jigoku hozo (hidden wedged tenon)

Name: Jigoku hozo (hidden wedged tenon) dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

How does a jigoku hozo joint work? · Hardware · basis: Xem Studio design — geometry computed in the generator from traditional proportions

Also called: jigoku hozo, 地獄ほぞ, hell tenon, hidden wedged tenon, fox wedged tenon, fox wedging, espiga acuñada oculta, verdeckt verkeilter Zapfen

Exact dimensions. True size, with no printing tolerance added.

length: 80.0 mm
width: 80.0 mm
height: 20.0 mm

Notes

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.

Jigoku hozo size chart

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

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Xem Studio

Joinery design (geometry computed in the generator from traditional proportions)

web

Xem Studio design

Free files

★ Free files 4 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

jigoku-hozo-hidden-wedged-tenon-mortised-member	Blind mortise flared 2 mm per side toward its bottom	STEP · STL
jigoku-hozo-hidden-wedged-tenon-tenon-member	Tenon split at its end, shown spread (assembled state)	STEP · STL
jigoku-hozo-hidden-wedged-tenon-wedge	Wedge sitting at the bottom of the mortise	STEP · STL
jigoku-hozo-hidden-wedged-tenon-assembled	All parts in their assembled position (each part its own solid)	STEP · STL

Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.

Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=jigoku-hozo-hidden-wedged-tenon