How can I cut aluminum angle stock without damaging my tools?
At work we cut aluminium with a drop saw. An sometimes our table saw. 
We have a drop saw set up just for aluminium, with a fine tooth blade. It don't really do any damage to it as long as you cut slow. 
aluminium is softer then some of the timber we cut. 
So anyway if your trying to cut neat cuts use drop saw. An shouldn't do damage. 
If you are worried use a angle grinder with a thin cutting blade.