Crank pin in a slotted yoke (Scotch yoke) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/scotch-yoke-crank-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 93 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- The crank pin runs in a slot across a sliding yoke, so the yoke moves exactly r·cos θ: simple harmonic motion with no connecting rod and no rod angularity — Brown's 'crank wrist in a slotted yoke'.
- Catalog Scotch-yoke parts, 30 mm stroke: crank pin at 15 mm carrying a 623 bearing in the 10 mm slot; drawn at 50°, the yoke 9.64 mm from centre. A guide block holds the rod straight.
- Brown's No. 93.
- Parts (each has its own page): scotch-yoke, ball-bearings-metric, scotch-yoke-rod-guide-8x8, dowel-pins-metric.
- Brown's movement No. 93 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
stroke  30 mm
crank radius  15 mm
slot  10 mm (623 bearing)
motion  x = 15 cos θ

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. 93: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_093.html

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