The first thing to do was to learn how to use a lathe and later on a vertical milling machine!
I AM Joking! 
Although these items of equipment were put to good use I could never have done this without the help and (Machinists view) of a good friend of mine Bert Wells (aka The Gremlin – private joke 
)
The first thing to do was to machine the aluminium rod down to size and then commence boring out the section that in a more conventional torch would house the batteries. In this lighthead, the hollow will actually hold the control electronics based on a PIC micro-controller part 12F683.
In previous (maglight) units I have placed the electronics in the sidemount battery cannister, but not on this design for reasons that will become apparent later.
Here is Bert machining the hollow for the Electronics:
And here we have a close up of the aluminium rod itself:
The fatter section on the left nearest the chuck will eventually house the MR16 globe.
A closeup – once things stopped spinning…
The next thing was to thread the inside of the housing ready to take the acrylic plug that will mount the cable gland and (optionally – there are two basic variants to the electronics design) a signalling LED.
More on this later on.