The Fluid AE sensor is ideal for situations where a direct AE contact is required in the grinding process. This can be situations where machine design or high frequency bearing, mechanical or electromagnetic noise prevent the use of other types of AE sensor. The Fluid AE sensor uses the existing grinding machine coolant which can be water or oil based. A separate feed from the cutting stream is taken from near the coolant filter and is directed at the component or dresser. The noise of the grinding wheel touching the component or dresser is then passed back up the coolant stream into the AE sensor where it is detected within 1 millisecond. The Fluid AE sensor comes with a polyurethane pipe that can be easily plumbed into the grinding machine coolant supply.