Geneva stop finger wheel: Ø4 pin at r 23.51, Ø41.02 locking disc, Ø6 bore — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/geneva-stop-finger-wheel-r23-5-pin4/  (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 53.02, width 53.02, height 10.0
- Driver of a Geneva (Maltese cross) stop for a star on 40 mm centres: one Ø4 × 6 pin at radius 23.51 (= a·sin(π/5), so it enters and leaves the star's slots radially), a Ø41.02 × 6 locking disc that holds the star still between indexings, and a Ø53.02 × 4 carrier plate under both; Ø6 bore.
- The locking disc is cut back by the exact sweep of the star through one indexing (the star's outline in the wheel's frame at every 0.1° of the 108° engagement, a clearance surface kept as 0 mm facets), so disc and star only ever touch: on the disc's rim while locked, on the pin while indexing.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
pin  Ø4 at r 23.51
locking disc  Ø41.02 × 6
carrier  Ø53.02 × 4
centres with the star  40 mm
engagement  ±54° of the wheel's turn
bore  Ø6

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. 212: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_212.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/geneva-stop-winding-stop-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/geneva-stop-finger-wheel-r23-5-pin4/index.json
API: https://xemstudio.com/api/geometry?object=geneva-stop-finger-wheel-r23-5-pin4