Constant-diameter cam for two Ø10 rollers 44 mm apart, 4 thick, Ø8 bore — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/constant-diameter-cam-c22-a6-b1-bore8/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
Catalog version: 2026-10-20

Overall (mm): length 34.42, width 34.0, height 4.0
- Plate cam whose roller-centre (pitch) curve is r = 22 + 6 sin θ − sin 3θ: opposite radii always add up to 44 mm, so two rollers 44 mm apart on one yoke touch it at every angle and the yoke is driven both ways with no spring. The profile is the pitch curve offset inward by the 5 mm roller radius (no undercut). Stroke 14 mm.
- Only odd harmonics are allowed in such a curve (r(θ) + r(θ + 180°) = constant); the sin 3θ term flattens the ends of the motion.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
pitch curve  r = 22 + 6 sin θ − sin 3θ
roller centres  44 mm apart
rollers  Ø10 (623 bearings)
stroke  14 mm
thickness  4 mm
bore  Ø8

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. 117: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_117.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/cam-between-rollers-yoke-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/constant-diameter-cam-c22-a6-b1-bore8/index.json
API: https://xemstudio.com/api/geometry?object=constant-diameter-cam-c22-a6-b1-bore8