From what I see in photo it is an extruded part cut to thickness maybe have the angle cut to, then the part is smoothed in a tumbler to deburr. As far as the angle of the part if it's a true triangle then the angle should be 45 degrees. Your best fix would be to first check your 2020 bar as they could also be bent or miss formed as well. As far as stress on the frame the amount of pressure putby Bluedragon456 - Reprappers