The app calculates RPM for lathe depending on material and its designation. How to use: 1. Select material, 2. Select designation, 3. Select Tool type, 4. Optionally change measurement units, 5. Enter work diameter. The app will calculate the RPM value. The following materials are supported: - Structural steel,
 - Plain carbon steels,
 - Resulfurized plain carbon steel, 
- Leaded plain carbon steels,
 - Resulfurized alloy steels,
 - Water hardening tool steel,
 - Cold work, oil hardening tool steel, 
- Cold work, air hardening tool steel,
 - Stainless steels (Austenitic),
 - Cast Iron,
 - Brass,
 - Bronze,
 - Copper,
 - Wrought aluminum,
 - Cast aluminum,
 - Machinable Wax,
 - Acetal Copolymer (Delrin),
 - Polyethylene,
 - Acrylic (with coolant),
 - Polycarbonate,
 - Teflon,
 - Nylon/Acetal,
 - Bakelite,
 - Hard rubber, 
- Wood. If you have any suggestions please let us know.