Tou Xiao (透销): The Through Pin for Heavy Aprons
Through pin
A planted pin (栽销) sits hidden between two members. On very heavy furniture that was not always enough.
The through pin is the same pin, lengthened to pass right through one of the members.
- Chinese
- 透销 · tòu xiāo
- Joins
- Heavy apron to frame
- Found in
- Large tieli and zitan beds and tables
- Signature parts
- Long pin · through hole · blind hole
- Related
- Planted pin (栽销)
How it works
A longer planted pin
A source on Qing furniture describes the through pin as a development of the planted pin: the pin is lengthened and passes right through the middle of one member.
Where
It is mostly found where the thick, heavy aprons of large tieli or zitan beds and tables meet the frame, and is very strong.
In the model
The pins pass up through the apron into blind holes in the frame; their number and positions are illustrative.
How it's made
Step 1Apron and frame
A heavy apron under the frame.
Step 2Through holes
Holes right through the apron.
Step 3Blind holes
Blind holes in the frame.
Step 4Long pin
A planted pin, made long.
Step 5Drive it up
Drive it up through the apron.
Step 6Strong
Very strong.
Variations
Planted pin
The short, hidden version.
Can you CNC this?
Yes, with small changes
The through holes and blind holes are plain drilling or pocketing from the faces. A round pin is easier than a flat one.
General note: a round cutter cannot leave a sharp inside corner, so every recess keeps the tool radius. Round the mating edges or add dogbone reliefs. Sloping faces, undercuts and curves may need special bits, extra setups or more axes.
Free STL downloads (one file per part)
- Frame side 大边 · tou-xiao-frame.stl
- Heavy apron 厚牙板 · tou-xiao-apron.stl
- Through pins (2) 透销（2 枚） · tou-xiao-through-pins.stl
Proportions are illustrative, not measured dimensions. The files are unitless: scale them to suit and check fits and allowances before cutting. Each file is a closed (watertight) solid with its mortises and slots already cut, exported in its assembled position, ready to import into CAM or modelling software. Licence: CC BY 4.0 (credit: Chinese Joinery).
Related joints
Loose Tenon
zāi xiāoThe tenon is a separate piece of wood planted into mortises in both parts, easy to replace if it wears.
Sliding Locking Key
zǒumǎ xiāoA dovetailed key planted in one part drops into the wide end of a slot and slides to the narrow end to lock.
Loose-Tenon Board Joint
zāisǔn pīnbǎnThick boards are joined edge to edge with separate straight tenons planted into mortises in both edges.
Questions
What is a through pin?
A planted pin lengthened to pass right through one member.
Where is it used?
Heavy aprons to frames of large beds and tables.
Does it show?
Its end shows on the face it passes through.