NOTE: 1. The thread conforms to ASME B1.20.1 NTP threads as described in Section 10. (The only exceptions are small male and female plain face threaded flanges which use NPSL recount threads.) 2. Class 150 threaded flanges are made without a counterbore. Threads are chamfered to the major diameter (approx.) at an angle of 45° (approx.) at the back of the flange. 3. Weights are based on manufacturer’s data and are approximate. 4. For tolerances +-0.5mm.