I bored the end for a 1/2" pipe tap and tapped it. Notice the marks on the tap so I can gauge when I'm getting close to the bottom.
After I finished taping the piece, I cut the part off the shaft with my bandsaw. I chucked it back up and faced it to length and bored the different steps that were required.
I then started on the body of the siren. It is a tube that is bored on one end to get silver soldered to the valve and the other end is threaded, so the rotor can be removed for cleaning.
That's all for now.