During milling and machining process, rotating Model 9125 measures vertical force and moment about spindle axis at speeds up to 25,000 rpm. Digital data measuring signal is transmitted without contact between dynamometer and stationary signal receiver/processor. Quartz sensors yield data response with threshold level of 0.007 lbf, and moment of 0.9 lbf-in. Unit weighs 3.3 lb and will not obstruct coolant flow.