The Gears Reference Guide

Our own drawings and a plain, sourced account of how gears work: pairs and pinions, counting teeth to work out ratios, spur, helical, bevel and worm gears, trains, and mechanical advantage.

What’s inside:

- What is a gear?

- Count the teeth

- Spur, helical, bevel and worm

- Trains, and mechanical advantage

- Credits, licence and sources

Pages: 9 (A4) / 9 (US Letter). Formats: A4 (210 × 297 mm) and US Letter (8.5 × 11 in), both PDFs included in one zip.

Printing: Print at 100% / actual size on A4 or US Letter. Most inside pages use light backgrounds and print well in black and white; the cover is dark, so print that in colour or skip it to save ink.

Every fact is written in our own words and checked against named sources from Encyclopaedia Britannica, OpenStax and the Science Museum Group (checked 14 Nov 2026); the sources are listed on the credits page. Where sources give different figures, each is shown with its source.

Drawings are our own, simplified and not to scale. This pack is independent and is not affiliated with, or endorsed by, Encyclopaedia Britannica, OpenStax or the Science Museum Group.

Licence: personal use. Print as many copies as you need for yourself and your household. Please don’t resell, re-upload or share it publicly. For club, school or commercial use, please email info@reallybyte.com.

Made by REALLYBYTE, the team behind gears.mechanics.im. Questions: info@reallybyte.com

This is a digital download: no physical item will be shipped.

Price: $5.99 USD.