[Tristan Lall]

7075 is great for machining, but doesn't work too well for sheet metal forming, because it's so strong and not especially ductile. (And you don't want to use anything with a torch or an arc on it: it's highly susceptible to stress cracking when welded or plasma-cut, and it will lose its heat treatment due to the heating.)

6061 can be formed if you give it a big enough radius, and isn't so strong that shearing it becomes impractical (but it's significantly more difficult than the grades of aluminum intended for sheet metal work). It's also weldable enough, if that is needed.

If you're set on sheet metal fabrication methods, and don't have rigourous strength concerns, then a 5052 would be easier to work with.

Also, if your pieces are small, it looks like you might be in the market for a table saw with a carbide blade. Cutting sheet metal on this is non-trivial, because of the need to support it properly, and the need to keep the workpiece nice and flat at all times. But for small stuff, it's very accurate, and very versatile. (This will easily get you within 0.125 in.) If you can deal with extruded flat bar stock, you can even use a radial arm saw to cut it in a similar way.

If you're looking at full-width pieces of sheet metal (like off of a coil or something), then a proper manual shear could work too. Alternatively, if the pieces are small, you could maybe use a small right-angle shear. They're great for light-duty sheet work involving small straight or right-angle cuts.

All of those methods will give good, straight edges, but will have burrs if sawn or a bit of deformation if shorn (so flatness suffers a little). If you're performing secondary machining on those edges with a mill, you'll be fine either way. Depending on the accuracy needed, those methods might also be able to eliminate the need for secondary machining: you can readily get tolerances down to the 16^th or 32^nd of an inch with proper preparation on a saw or a shear.