Slotted guide bar 150 × 30 × 6, Ø8 pivot hole and 8 mm slot for a sliding pinion shaft — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/slotted-guide-bar-150-slot8-elliptical/  (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 150.0, width 30.0, height 6.0
- Fixed bar with a Ø8 hole for the elliptical gear's shaft and, on the same line, an 8 mm slot from 32.53 to 48.2 mm along it: the pinion's Ø8 shaft slides in the slot so the pinion follows the gear's changing radius (its centre travels 36.53 – 44.2 mm from the gear's centre); a spring or weight keeps it in mesh.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
bar  150 × 30 × 6 mm
pivot  Ø8 at 0
slot  8 mm, centres 32.53 … 48.2 mm

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. 35: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_035.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/elliptical-gear-pinion-slotted-bar-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/slotted-guide-bar-150-slot8-elliptical/index.json
API: https://xemstudio.com/api/geometry?object=slotted-guide-bar-150-slot8-elliptical