Grooved (wedge) friction gearing, 30 : 60 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/grooved-friction-wheels-mechanism/  (CC BY 4.0)
Basis: Xem Studio design following Brown No. 45 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Ridges on one wheel wedge into matching V-grooves on the other: pressed together with force F, the normal force on the flanks is F / sin(α/2), so with 67.38° grooves the grip is about 1.8 times that of plain wheels at the same pressure.
- Ratio by pitch diameters, 60/30 = 2 : 1, centres 45 mm; the two profiles are exact complements on the line of centres (touching flanks, no overlap).
- Brown's No. 45 (friction gearing with grooves, shown in section).
- Parts (each has its own page): grooved-friction-wheel-30, grooved-friction-wheel-60.
- Brown's movement No. 45 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
wheels  pitch Ø30 and Ø60 × 16
grooves  4 mm pitch, 67.38°
centres  45 mm
grip gain  ≈ 1.8×

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. 45: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_045.html

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