Chinese JoineryChinese Joinery
中文
Mitred frames and panels
攒斗
cuándòu

Cuandou (攒斗): Openwork Lattice Built from Short Pieces and Loose Tenons

Cuandou · Cuandou lattice · 攒斗 · Lantern lattice

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The openwork panels of Ming bed railings and cabinet doors look carved, but most are built from many short pieces.

Each butt joint is held by a tiny hidden tenon. This kind of work is called cuandou.

Chinese
攒斗 · cuándòu
Joins
Short straight pieces to each other and to the frame
Found in
Bed railings, open shelves, lattice doors
Signature parts
Short pieces · butt joints · loose tenons
Compare
Carved spacer with loose tenons
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How it works

Many short pieces

Patterns such as the lantern lattice are not cut from one board. They are put together from many short straight pieces, each butted against its neighbours or against the frame.

Loose tenons at every butt

A short piece is too small to carry its own tenon across the grain, so each butt joint gets a small separate tenon (栽榫) set into both pieces. Wang Shixiang lists these lattice patterns, such as four-way cloud and cross-and-square designs on bed railings and cabinet doors, among the places where loose tenons are used. His drawing of a lantern lattice marks a small tenon at each butt.

What you see

From the front only the fine joint lines show; the tenons stay inside.

How it's made

  1. Lattice
    Step 1

    Lattice

    A lattice of short pieces.

  2. Short pieces
    Step 2

    Short pieces

    Each piece is short and straight.

  3. Loose tenons
    Step 3

    Loose tenons

    Small separate tenons.

  4. To the frame
    Step 4

    To the frame

    A piece is joined to the frame.

  5. To each other
    Step 5

    To each other

    Pieces are joined to each other.

  6. Hidden
    Step 6

    Hidden

    No tenon shows on the face.

Variations

Patterns

Lantern lattice, four-way cloud, cross-and-square and similar designs use the same method.

Can you CNC this?

Yes, with small changes

Every short piece is a straight bar with a small pocket in each end, and the loose tenons are tiny rectangular sticks; all are simple 3-axis cuts. The small pockets need a small bit, and their round corners need squaring or rounded tenons.

Free STL downloads (one file per part)

Before cutting or printing, read the CNC and 3D-printing notes on tool radius, scaling the STL files and their licence.

Questions

Why loose tenons?

The pieces are too short to cut sound tenons of their own.

Where is it used?

Bed railings, open shelves and lattice doors.

Is it carved?

No. It is assembled from many small pieces.

Further reading
  1. 王世襄《明式家具研究》（Wang Shixiang, Research on Ming Furniture），第 118 页，图 3.44a
  2. 王世襄《明式家具研究》（Wang Shixiang, Research on Ming Furniture），第 119 页