Stepped (speed-cone) pulley Ø50 / Ø40 / Ø30 × 20 mm steps, Ø8 bore — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/stepped-cone-pulley-50-40-30/  (CC BY 4.0)
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 60.0
- Three flat-belt steps Ø50, Ø40 and Ø30, each 20 mm wide (60 mm total), Ø8 bore. Two identical cones mounted the opposite way round keep the same belt length on each step pair (the diameters sum to 80 every time).
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
steps  Ø50 / Ø40 / Ø30
step width  20 mm
bore  Ø8

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. 8: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_008.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/stepped-cone-pulleys-mechanism/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/stepped-cone-pulley-50-40-30/index.json
API: https://xemstudio.com/api/geometry?object=stepped-cone-pulley-50-40-30