All screws on Neumann mics are, and always have been, metric (there are exactly THREE countries in the world which do nor use the metric system: Liberia, Myanmar and of course, the United States of America).
But in order to help you, I need more information:
Which three screws are you referring to? The ones that hold the head basket to the body (Philips oval)?
Or the ones that affix the head assembly base plate to the head basket (fillister slot)?
