The aluminum angle for making the tank attach brackets wasn't very square. We cut the brackets to length and then took them into work to use the hydraulic press to square them up. This picture isn't very good, but shows a squared bracket on the bottom and a non-squared one (actually the leftover piece of stock) on the top.

Here's what they looked like before squaring them up.

...and here's what they looked like after squaring. Much better. :-)

The plans show the radius to use. I've just finished the rough cuts on the band saw. You may notice that I didn't do the taper exactly like the plans show. On the drawing, the taper kind of flares out near the base of the bracket. I took the easy way out and just made it straight.