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Lewis (three-piece stone lifter in a dovetail hole)

How does a lewis lift a stone? · Hardware · basis: Xem Studio design following Brown No. 493 (1868)

Also called: lewis, lewis pin, stone lifting lewis, dovetail stone lifter, castañuela (lewis), Steinwolf (Wolf)

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

sizes
4 in table

Notes

  • A dovetail hole is cut in the top of the stone; the two tapered side pieces go in first, then a parallel centre piece between them pushes them out into the undercut. A pin through all three takes the hoisting shackle: pulling up jams the wedges against the dovetail's sloping walls, so the stone cannot slip off.
  • Hole 20 → 30 mm over 30 mm depth, 14 mm wide; centre piece 10 mm, side wedges 5 → 10 mm, so the three fill the dovetail exactly (contact on every face, no overlap); Ø6 pin 12 mm above the stone. To release, lift the centre piece out first.
  • Brown's No. 493 (lewis, for raising stones); in use since Roman times.
  • Parts (each has its own page): lewis-stone-block-80x60x50, lewis-centre-piece-10x14x50, lewis-side-wedge-5-10x14x50, dowel-pins-metric.
  • Brown's movement No. 493 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Lewis size chart

parametervalue
hole20 → 30 × 14, 30 deep
centre piece10 × 14 × 50
side wedges2 × (5 → 10) × 14 × 50
pinØ6 × 40

Where the files are

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

Henry T. Brown (1868, public domain)Five Hundred and Seven Mechanical Movements — scan on archive.orgwebPublisher's page; dimensions are facts
507movements.comBrown's movement No. 493: figure, his text and an animationwebPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

lewis-stone-lifter-mechanism-assemblyAssembled mechanism, all parts placed at one pose (STEP keeps each part separate)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=lewis-stone-lifter-mechanism

Lewis (three-piece stone lifter in a dovetail hole), isometric render of a generated part
Render of lewis-stone-lifter-mechanism-assembly from the free STEP; not to scale.

Fits with

Stone block 80 × 60 × 50 with a dovetail lewis hole 20 → 30 × 14, 30 deep, isometric render of a generated part
Stone block 80 × 60 × 50 with a dovetail lewis hole 20 → 30 × 14, 30 deep80.0×60.0×50.0 mm★ 1 file
Lewis centre piece 10 × 14 × 50, Ø6 pin hole, isometric render of a generated part
Lewis centre piece 10 × 14 × 50, Ø6 pin hole10.0×14.0×50.0 mm★ 1 file
Lewis side wedge 5 → 10 × 14 × 50, Ø6 pin hole, isometric render of a generated part
Lewis side wedge 5 → 10 × 14 × 50, Ø6 pin hole10.0×14.0×50.0 mm★ 1 file
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325), isometric render of a generated part
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)5 sizes★ 23 files

Questions

How does a lewis lift a stone?

A dovetail hole is cut in the top of the stone; the two tapered side pieces go in first, then a parallel centre piece between them pushes them out into the undercut. A pin through all three takes the hoisting shackle: pulling up jams the wedges against the dovetail's sloping walls, so the stone cannot slip off.