I set up models for a punch and die with 0.004" clearance. When cut out on a CNC I couldn't fit the parts together. I did the finishing light pass climb cutting. I need to do some measurements but apparently the end mills don't cut quite as big as the nominal size. Someone suggested doing a test pocket of a simple shape to check how close to size the milling will be. Can someone enlighten me on some ways to deal with this issue?