This document discusses methods for balancing rotating machinery using a mobile phone stopwatch to time oscillations. The Timed Oscillation Method involves attaching a swing mass to the rotor and using a phone stopwatch to time oscillations. Times are plotted against position and the maximum/minimum times are used to calculate an imbalance correction mass. This method was successfully used to balance pump impellers and fans. The document also discusses trial and error balancing without instrumentation by drilling holes in positions that cause rotor oscillations to vary.