Barrel (cylindrical) cam with pin follower — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/barrel-cam-mechanism/  (CC BY 4.0)
Basis: Xem Studio drawing; classic mechanism (Brown No. 106)
Catalog version: 2026-10-20

Sizes: see table below
- A groove cut round a cylinder carries a follower pin: one turn moves the pin along the axis by the groove's rise and back. Here a sine groove gives 15 mm of simple-harmonic stroke.
- Groove shape sets the motion: a helix reversed at the ends gives uniform speed (Brown's grooved cylinder), a sine gives smooth harmonic motion.
- Used in sewing machines, fishing reels' level wind and indexing tables.
- Parts (each has its own page): barrel-cam-r20-h15, dowel-pins-metric. Brown's movement No. 106 shows it (1868).

parameter  value
cylinder  Ø40 × 50 mm
stroke  15 mm
groove width  6.4 mm (Ø6 pin)

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

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