Cutting Aluminum Sheet Straight and Long

Hi.



So after much wailing and gnashing of teeth I finally get it. Making your own C-Channel totally makes sense. (Someone tried to tell me this but I had my head up me bum…. I get it now. Thanks)



I figured out where in my shop to make a nice 8 foot brake.



Question: How Do I cut perfectly straight lines in a sheet of 4 x 8 foot .040 5052h32 aluminum sheet?



I need to cut the entire sheet into 4.5 inch strips so I can brake those into 1.5 x 1.5 x 1.5 inch C-Channel. Easy peasy. I think?



I have harbor freight sheers but should I really try to free hand it?



My first thought is some kind of kick ass box cutter/wheel type pizza cutter gizmo? I just made that up ….



Any advice welcome.



Thanks