Stepped (staggered) spur gearing, 20 : 40, two steps — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/stepped-gearing-mechanism/  (CC BY 4.0)
Basis: Xem Studio design following Brown No. 44 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Each wheel is two identical spur gears side by side, the second turned by half a tooth pitch: the steps share the load so that one pair is always near the pitch point, giving smoother, stronger drive — the step towards helical gears.
- Built here from four catalog module 1 gears (20 and 40 teeth), the upper layer turned 9° (pinion) and 4.5° (wheel); centre distance 30 mm, no backlash drawn.
- Brown's No. 44 notes its use for heavy, slow drives such as large planing-machine beds.
- Parts (each has its own page): spur-gears-module-1.
- Brown's movement No. 44 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
module  1
teeth  20 / 40, two layers each
layer offset  half a pitch (9° / 4.5°)
centre distance  30 mm
face  2 × 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. 44: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_044.html

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