Pin-clutch disc Ø50 × 8 with four Ø6 × 10 studs, Ø8 bore with 2 mm keyway — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/pin-clutch-disc-4-studs-50-keyed/  (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 50.0, width 50.0, height 18.0
- Ø50 × 8 disc with four Ø6 × 10 studs on a 16 mm radius; its Ø8 bore has a 2 × 1 keyway so it slides on a feather key: pushed along, its studs enter the other disc's holes.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
disc  Ø50 × 8
studs  4 × Ø6 × 10 on R16
bore  Ø8, keyway 2 × 1

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. 52: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_052.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/pin-clutch-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/pin-clutch-disc-4-studs-50-keyed/index.json
API: https://xemstudio.com/api/geometry?object=pin-clutch-disc-4-studs-50-keyed