Slotted bell crank: 100 mm arm with a 6.4 slot (50–90 mm) and a 50 mm arm at 90°, Ø5 bore — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/slotted-bell-crank-100-50-slot-50-90-b5/  (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 115.0, height 8.0
- 8 mm plate pivoted on a Ø5 pin: one arm 16 wide and 100 long with a 6.4 mm slot from 50 to 90 mm out for a crank pin's slide block, the other 12 wide with a Ø3 hole 50 mm out at 90°.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
slotted arm  100 mm, 6.4 slot 50–90
second arm  50 mm at 90°, Ø3 hole
bore  Ø5
thickness  8 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. 156: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_156.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/crank-slotted-bell-crank-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/slotted-bell-crank-100-50-slot-50-90-b5/index.json
API: https://xemstudio.com/api/geometry?object=slotted-bell-crank-100-50-slot-50-90-b5