Of all the things to find in your garage, a mill is probably the perfect one for this project.
From what I've heard, being able to make your own parts is the only way RC heli's are an affordable hobby On Rhino 3D - I agree. I can't find the time to learn it properly, and when I try, I don't use it enough and forget everything
McMaster have a good page with characteristics of most of the common steels: http://www.mcmaster.com/#steel/=1pb36r - no doubt there's better out there, but it's a start. I bought my steel from Corus - you probably have a local branch somewhere near you? I'm using a free machining grade stock, it cuts nicely and gives a decent finish but more importantly, it seems to stay straight after machining... I'm sure you could use some, if not most of what you already have though.
Ps - is that the beginnings of a RAID array beside the drawers?