Conoid (curved cone) pulley Ø24–Ø56 × 64, profile for constant open-belt length at 110 mm — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/conoid-pulley-24-56x64-bore8/  (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 71.26, width 71.26, height 64.0
- A pair of these, mounted head to tail 110 mm apart, keeps an open belt at exactly the same length wherever it runs: the generatrix is r(z) = (s + 2g)/2 with g = (z − 32)/4 and s chosen so 2√(C² − d²) + πs + 2d·asin(d/C) stays 2C + 40π (d = −2g).
- The curve bulges up to 8.37 mm outside a straight cone near the ends; a flat belt touches it on its centre line.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

dimension  value
diameters  Ø24 → Ø56
length  64 mm
profile  exact constant-belt-length curve for C = 110
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. 10: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_010.html
- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/conoid-pulleys-mechanism/

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/conoid-pulley-24-56x64-bore8/index.json
API: https://xemstudio.com/api/geometry?object=conoid-pulley-24-56x64-bore8