Xem Studiomeasured geometry

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Screw jack, Tr16×4 (4 mm lift per turn)

How much force does a screw jack give? · Hardware · basis: Xem Studio design following Brown No. 389 (1868)

Also called: screw jack, jack screw, lifting jack, bottle jack screw, gato de tornillo, Schraubenwinde (Spindelheber)

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

sizes
4 in table

Notes

  • Turning the screw in its threaded body lifts it one pitch per turn (4 mm). Ideal force gain = 2π × lever radius / pitch: 2π × 40 / 4 ≈ 63 with the 80 mm tommy bar; friction in the 30° thread takes about two-thirds of that and keeps the load from running back.
  • Basic-profile Tr16×4 trapezoidal thread on screw and body, drawn engaged with no allowance.
  • Brown's No. 389 (lifting jack).
  • Parts (each has its own page): screw-jack-screw-tr16x4, screw-jack-body-tr16x4, tommy-bar-6x80.
  • Brown's movement No. 389 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Screw jack, Tr16×4 size chart

parametervalue
threadTr16×4
lift per turn4 mm
lever radius40 mm
ideal gain≈ 63

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

Free files

★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json

screw-jack-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.
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Plain text: sheet.txt · JSON: /api/geometry?object=screw-jack-mechanism

Screw jack, Tr16×4 (4 mm lift per turn), isometric render of a generated part
Render of screw-jack-mechanism-assembly from the free STEP; not to scale.

Fits with

Screw-jack screw Tr16×4, 90 mm thread, Ø28 head with tommy-bar holes, isometric render of a generated part
Screw-jack screw Tr16×4, 90 mm thread, Ø28 head with tommy-bar holes28.0×28.0×106.0 mm★ 1 file
Screw-jack body with Tr16×4 internal thread, Ø60 base, 50 high, isometric render of a generated part
Screw-jack body with Tr16×4 internal thread, Ø60 base, 50 high60.0×60.0×50.0 mm★ 1 file
Tommy bar Ø6 × 80, isometric render of a generated part
Tommy bar Ø6 × 8080.0×6.0×6.0 mm★ 1 file

Questions

How much force does a screw jack give?

Turning the screw in its threaded body lifts it one pitch per turn (4 mm). Ideal force gain = 2π × lever radius / pitch: 2π × 40 / 4 ≈ 63 with the 80 mm tommy bar; friction in the 30° thread takes about two-thirds of that and keeps the load from running back.