Friction wheels (rolling contact drive), 30 : 60 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/friction-wheels-mechanism/  (CC BY 4.0)
Basis: Xem Studio design following Brown No. 32 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Two plain wheels pressed together drive each other by friction at the line of contact: ratio = D₂/D₁ (2 : 1 here), opposite directions, and they slip instead of breaking when overloaded.
- Torque at the small wheel ≈ μ·F·R₁: with rubber on steel (μ ≈ 0.6) and 50 N pressing, about 0.45 N·m. Centre distance = (D₁ + D₂)/2 = 45 mm, rims touching.
- Brown's No. 32 (friction wheels with roughened or leather/rubber-covered rims).
- Parts (each has its own page): friction-wheel-30x10, friction-wheel-60x10.
- Brown's movement No. 32 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
wheels  Ø30 and Ø60 × 10
centre distance  45 mm
ratio  2 : 1

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala
- 507movements.com: Brown's movement No. 32: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_032.html

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/friction-wheels-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=friction-wheels-mechanism