So today I assembled all the parts and got cracking. Drilling the holes worked well - the fit was perfect.
The drill bit for 3/4" pipe parts: I did snap both of the drill guides in getting this done, but that's mostly because I am new to drilling metal.
I tried out the holes on some thin metal first before drilling the barrel - it all fit perfectly and threaded straight in:
The three air inlets in - 2 x 3/4" pipes and 1 x 1" pipe for the ball-valve:
One of the 3/4" inlets with the cap showing:
These are the u-bolts I will use to support the 2 grills:
Starting to grind out the inside:
The 1" ball-valve:
The lid - stripped of paint, and with 2 new air inlets and the handle:
That's it for now - the barrel is burning away and the outside paint is melting off, but I wont be getting anything more done until next week, when my grills should be ready (no Weber here :( )
Couldn't have done this without this great thread!