Gear ratios, worm drives, rack and pinion, and belt drive velocity ratios

What this note covers

1. Identify driver and driven before calculating the ratio
2. Idlers alter routing and direction without changing the endpoint ratio
3. Compound trains multiply stage ratios
4. Belt drives depend on pulley geometry and traction
5. Worm gearing and rack-and-pinion create different outputs
6. Audit a combined drive stage by stage
7. Worked compound drive: belt stage followed by two gear meshes
8. Worked rack-and-pinion case: convert motor turns to linear travel

8 sections · 10 key terms & formulas · 6 common mistakes