Housing plate 70 × 40 × 6 with a Ø16 bush bore — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/back-gear-housing-plate-70x40/  (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 70.0, width 40.0, height 6.0
- 70 × 40 × 6 plate with a Ø16 bore for the eccentric bush and four Ø3.4 (M3) holes; it is fixed 2.5 mm further from the spindle than the engaged pinion axle.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
plate  70 × 40 × 6
bore  Ø16
holes  4 × Ø3.4

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. 56: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_056.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/eccentric-back-gear-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/back-gear-housing-plate-70x40/index.json
API: https://xemstudio.com/api/geometry?object=back-gear-housing-plate-70x40