... for geological prospecting,oilfield drilling,coal ecploration,water conservancy and power engineering fields,etc.Available sizes of the NQ series ... mm1.0±0.1 mmPCD/PDC diamond cutters for coal mining bits, diamond bitWe manufacture PCD drill bits (PDC core ... geological prospecting,oilfield drilling,coal ecploration,water conservancy and power engineering fields,etc.Available sizes of the NQ series ...