Train arm 64 × 14 × 5 with three Ø6 holes at 25 mm (Ferguson's paradox) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/paradox-arm-25-25-b6/  (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 64.0, width 14.0, height 5.0
- 14 × 5 mm arm with Ø6 holes at 0, 25 and 50 mm: it turns on the fixed sun's Ø6 stud and carries the thick idler on the middle pin and the three paradox wheels on the end pin.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
holes  3 × Ø6 at 0 / 25 / 50 mm
section  14 × 5 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. 504: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_504.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/fergusons-paradox-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/paradox-arm-25-25-b6/index.json
API: https://xemstudio.com/api/geometry?object=paradox-arm-25-25-b6