Hello again, Having now found the screw threads, and edited them and admired them from many different angles, I find myself having a blonde moment... When you create a screw thread, it draws a ring to represent some of the dimensions of the thread. My question to you the world in general, is does this line represent the largest/smallest diameter of the thread, or is it the pitch diameter? For example, I would like to make two components which screw together. The outside diameter of the inner piece and inside diameter of the outta is 35mm. When applying a (BSI) thread to the outta, a 35mm diameter selection will only allow me to select a 39x2 thread minimum, and the line drawn on the model has a diameter of 39. On the inner, I can select a 36x2 thread, but the line drawn has a diameter of 33.8mm which as far as i know is the pitch diameter of a 36x3 thread. Can't can I just model two pieces that mate up, and apply a possitive and negative M36x2 thread to both sides? Confused.