Belt drive between shafts at right angles with two guide pulleys — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/guide-pulley-right-angle-belt-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 3 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Two pulleys on shafts at right angles, joined by one belt led over two guide pulleys on a single inclined shaft. Each strand lies in the mid-planes of both pulleys it joins, so the belt runs in either direction without leaving the faces.
- Here two Ø40 pulleys sit 80 mm apart on the common perpendicular, their belt lines all parallel; the guides (Ø28.28 = 20√2) are 100 mm beyond, on a shaft at 45° to both. Each strand twists 45°; belt 12 × 1.5, inside length 774.52 mm.
- Brown's No. 3 (guide pulleys carrying the belt between shafts at right angles); No. 4 does it with the belt alone, working one way only.
- Parts (each has its own page): plain-flat-pulley-40x12, plain-flat-pulley-28-28x12-bore6, flat-belt-12x1-5-right-angle-guide-drive, dowel-pins-metric.
- Brown's movement No. 3 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
pulleys  2 × Ø40 × 12, shafts at 90°
guide pulleys  2 × Ø28.28 on one shaft at 45°
ratio  1 : 1
belt  12 × 1.5, 774.52 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. 3: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_003.html

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/guide-pulley-right-angle-belt-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=guide-pulley-right-angle-belt-mechanism