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Round-groove pulleys and round band, 1 : 1

Name: Round-groove pulleys and round band, 1 : 1 dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

How does a round band sit in a round-groove pulley? · Hardware · basis: Xem Studio design following Brown No. 257 (1868)

Also called: round belt drive, grooved pulley, o-ring belt drive, poleas de garganta redonda con correa redonda, Rundriemenscheiben mit Rundriemen

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

sizes: 4 in table

Notes

The band's section matches the groove, so it is held on half its circumference and cannot ride off; it drives by friction on the groove's surface, like a flat belt but steerable round guide pulleys at any angle.
Two equal pulleys 100 mm apart on Ø8 shafts and a Ø5 endless band, drawn seated in both grooves (band centre radius 20 mm).
Brown's No. 257.
Parts (each has its own page): round-groove-pulley-40-band5-bore8, round-band-5-c100-pulleys-40, linear-shafts-h6.
Brown's movement No. 257 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Round-groove pulleys and round band, 1 : 1 size chart

parameter	value
pulleys	2 × Ø40 × 10 for a Ø5 round band
band	Ø5 round
centre distance	100 mm
ratio	1 : 1

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.org	web	Publisher's page; dimensions are facts
507movements.com	Brown's movement No. 257: figure, his text and an animation	web	Publisher'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

round-groove-pulleys-round-band-mechanism-assembly

Assembled 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=round-groove-pulleys-round-band-mechanism

Round-groove pulleys and round band, 1 : 1, isometric render of a generated part — Render of round-groove-pulleys-round-band-mechanism-assembly from the free STEP; not to scale.

Fits with

Free

Round-groove pulley Ø40 × 10 for a Ø5 round band, Ø8 bore, isometric render of a generated part

Round-groove pulley Ø40 × 10 for a Ø5 round band, Ø8 bore40.0×40.0×10.0 mm★ 1 file Free

Round band Ø5, endless, 325.66 mm centreline, on two pulleys 100 mm apart, isometric render of a generated part

Round band Ø5, endless, 325.66 mm centreline, on two pulleys 100 mm apart145.0×45.0×5.0 mm★ 1 file Free

Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long, isometric render of a generated part

Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long10 sizes★ 70 files

Questions

How does a round band sit in a round-groove pulley?

The band's section matches the groove, so it is held on half its circumference and cannot ride off; it drives by friction on the groove's surface, like a flat belt but steerable round guide pulleys at any angle.