Scott Russell straight-line linkage (half-scissor) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/scott-russell-straight-line-mechanism/  (CC BY 4.0)
Basis: Xem Studio design following Brown No. 339 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- A bar AB of length 2r has its midpoint C pinned to a radius link OC = r; end A slides on a straight guide through O. Because A, B and O always lie on a circle round C, B moves on the exact straight line through O at right angles to the guide.
- Here r = 40: bar 80 mm (centre-hole link), radius link 40 mm, A in a 6.2 mm slot; at 35° B is 45.89 mm up the perpendicular. A moves 80·cos φ, B 80·sin φ.
- Brown's No. 339 (bar on the rod, one end sliding in a fixed slot, radius bar to its middle).
- Parts (each has its own page): centre-hole-link-80, four-bar-links, slot-guide-plate-90, slide-block-12x6, dowel-pins-metric.
- Brown's movement No. 339 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
bar AB  80 mm
radius OC  40 mm
guide  6.2 mm slot
path of B  exact straight line

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. 339: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_339.html

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