2.5" BSP Thread (I think)

This is just a 2.5" BSP thread. I'm not sure if I got the measurements right but it's parametric, so you can modify the parameters. I used [this diagram](https://en.wikipedia.org/wiki/British_Standard_Whitworth#/media/File:Whitworth_Thread.svg)
(along with the measurements on the associated article) as the basis for the profile.