ShaftCPM Lite

Try it free. Lay your phone on the desk and pluck to see the shaft's natural frequency in CPM. Up to 3 measurements per day; an unlimited paid version is available.

ShaftCPM Lite is the free version of a spectrum analyzer that measures a golf shaft's natural frequency in CPM (cycles per minute) in real time.

You don't attach your phone to the club. Clamp the club to the edge of a desk, lay your iPhone flat on the desk, pluck the shaft, and tap Start. The frequency appears as a large number and a graph. Because nothing is attached to the club, its mass doesn't lower the frequency, giving good absolute accuracy.

■ About the free version ・Up to 3 measurements per day, about 10 seconds each. ・For unlimited measurements with no time limit, please use the paid version, "ShaftCPM."

■ Features ・Real-time CPM: analyzes the shaft's vibration and shows the natural frequency in large type. ・Spectrum & peak detection: plots the vibration spectrum and automatically detects the peak (natural frequency), with an approximate ± range. ・Desk-placement method: nothing is attached to the club, so its mass doesn't lower the reading. ・Portrait & landscape layouts; Japanese / English.

■ Please note Readings are approximate. Please use them as a reference, not as exact frequency measurements. They are more than adequate for comparing how stiff or soft your shafts are.

This app uses only the accelerometer—no microphone, camera, or location. It collects and transmits no personal information or data.