LatheGearProSmart Gear Calculation
Finds all valid gear combinations that produce the ratio needed for your desired thread pitch, up to 4 gear pairs deep.
Metric & Imperial
Handles metric-to-imperial and imperial-to-metric conversions automatically. Supports 127T, 63T and other conversion gears.
Lathe Profiles
Save multiple lathe profiles with different leadscrews and gear sets. Switch between lathes instantly.
Fully Offline
All calculations run locally on your device. No internet connection required, no data collected.
When Is This Useful?
- Your lathe's standard gear chart doesn't include the thread pitch you need
- You're missing some of the standard gears and need an alternative arrangement
- You want to verify a gear setup before cutting
- You're working with metric threads on an imperial lathe (or vice versa)
- You want higher accuracy than your lathe manufacturer suggests
- You don't need high accuracy and want to cut a thread without purchasing additional gears
How It Works
Enter your leadscrew specification, the thread you want to cut, and a list of the change gears you have available. LatheGearPro calculates every valid gear combination and presents results sorted by number of gears and accuracy. Set an error tolerance to find approximate matches when an exact ratio isn't possible with your available gears.