Jockey (tightener) lever, 51.48 mm centres, Ø6 holes — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/jockey-lever-bore6/  (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 103.48, width 12.0, height 5.0
- 12 × 5 mm flat lever with a Ø6 pivot hole and a Ø6 hole 51.48 mm away, and a 40 mm handle beyond it.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
centres  51.48 mm
holes  Ø6 / Ø6
section  12 × 5 mm
handle  40 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. 5: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_005.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/jockey-pulley-belt-tightener-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/jockey-lever-bore6/index.json
API: https://xemstudio.com/api/geometry?object=jockey-lever-bore6