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Variable-crank disc Ø80 × 6 with a 6 mm Archimedean spiral slot (R8 → R34 in one turn)

How does the spiral plate set the crank radius? · Modern device · basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance

Also called: spiral plate, scroll plate, disco de ranura espiral, Spiralscheibe

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

length
80.0 mm
width
80.0 mm
height
6.0 mm

Notes

  • Ø80 × 6 disc with a 6 mm slot along an Archimedean spiral rising 26 mm in one turn: turning it against the radial-slot disc slides the pin in or out, 26/360 mm per degree; clamp it to fix the throw.
  • Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

Variable-crank disc Ø80 × 6 with a 6 mm Archimedean spiral slot size chart

dimensionvalue
discØ80 × 6, Ø8 bore
spiralR8 → R34, one turn, 6 mm slot

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. 94: figure, his text and an animationwebPublisher's page; dimensions are facts
Xem StudiodrawingwebPublisher'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

variable-crank-disc-spiral-slot-80as drawn in the mechanism's own frameSTEP · 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=variable-crank-disc-spiral-slot-80

Variable-crank disc Ø80 × 6 with a 6 mm Archimedean spiral slot (R8 → R34 in one turn), isometric render of a generated part
Render of variable-crank-disc-spiral-slot-80 from the free STEP; not to scale.

Fits with

Variable crank: a spiral-slotted plate moves the pin along a radial slot, isometric render of a generated part
Variable crank: a spiral-slotted plate moves the pin along a radial slot3 sizes★ 1 file

Questions

How does the spiral plate set the crank radius?

Ø80 × 6 disc with a 6 mm slot along an Archimedean spiral rising 26 mm in one turn: turning it against the radial-slot disc slides the pin in or out, 26/360 mm per degree; clamp it to fix the throw.