Centrifugal (fly-ball) governor — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/flyball-governor-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 161 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Two balls on arms hinged to the head of a spinning spindle fly outward as it turns faster; links from the arms lift a sleeve on the spindle, and the sleeve works the steam throttle (or any regulator), closing it as speed rises. Each ball settles where tan α = ω² r / g: at α = 30° and r = 54 mm the spindle turns 97.8 rpm.
- Arms 80 mm (Ø24 balls), pivots 14 mm from the axis, links 40 mm from the arms' midpoints to the sleeve; drawn at α = 30°, the sleeve pins 69.28 mm below the arm pivots.
- Brown's No. 161 (Watt's governor).
- Parts (each has its own page): governor-arm-80-ball-24, governor-head-16-ears-14, governor-sleeve-16-ears-14, four-bar-links, dowel-pins-metric, linear-shafts-h6.
- Brown's movement No. 161 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
arms  2 × 80 mm, Ø24 balls
links  2 pairs × 40 mm
angle drawn  30°
speed at that angle  97.8 rpm

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. 161: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_161.html

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/flyball-governor-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=flyball-governor-mechanism