In another segment of KITPLANES’ Metal Magic series, editor at large Paul Dye shows you how to accurately cut and artfully shape even large and thick aluminum angles.
This series is sponsored by Aircraft Spruce & Specialty.
View the complete list of published Metal Magic videos.
Very nice information. If I may add my $0.01 if you don’t have a bandsaw or on some of the complicated cuts you can use 3-4″ angle grinder with a cutoff wheel. In fact I find myself grabbing it more often than not. I have a small and large Vice just for that purpose. The Jaws are fitted with nylon instead of knurled Steel. This prevents marring of the aluminum. Then to finish the part I can use either the belt drum or disc Sanders. And I almost always knock the corners off. Not only does it give a cleaner look but inevitably you will bump part of your body against that sharp corner, and it won’t be good. LOL
It looks like you were cleaning up your aluminum with a grindstone and not a sanding wheel although you did say Scotchbrite just before you started. Using a Grindstone embeds aluminum particles in the wheel and can cause the stone to explode. https://web.mit.edu/course/other/machineshop/Grinder/aluminum.html
A Scotchbrite wheel which is the right tool. In the video though this looks like a regular grinding wheel and some people may not realize that’s not what you were using. It might be worth a specific comment that these were not stone wheels in your grinder but Scotchbrite that looks like grinding wheels. An example of what I use is https://www.3m.com/3M/en_US/metalworking-us/products/scotch-brite-wheels/
Both wheels on Paul’s bench grinder are Scotchbrite – the left one is new and still has square edges, while the one on the right has been around longer.
45- and 30-60-degree drafting triangles for marking purposes are cheap and much easier and faster to use. You can also buy adjustable drafting triangles to simplify marking for odd angles. Additionally, plastic drafting curves are also very useful in the shop. They come in clear or translucent colors.
You may have discussed this in a different video but I did not see it in this video. You should talk about the kind of bandsaw blade that best cuts aluminum. I had a friend come to my hanger to ask if I had a spare metal cutting band saw blade as his had just broke when cutting an aluminum angle. I cut it on my band saw with a very aggressive wood cutting blade and he was amazed at how easily the blade cut through the angle. He was very surprised that a wood cutting blade made cutting aluminum that easy. I forget how many TPI I had in my blade but it can be pretty aggressive and work fine. A metal cutting blade is definitely not what should be used.