That machine you are showing is actually a shear AND a brake AND a roll. I have just ordered a similar machine from Baileigh (50 inch, 16ga CRS capacity)...
http://www.baileighindustrial.com/shears/sbr-5216.php
The issue is that the 0.080 sheet you want to cut straight is pretty heavy, for 'sheet metal' (looks like it works out to be '12 gauge' on the gauge charts)...
http://www.unc.edu/~rowlett/units/scales/sheetmetal.html
Most of the little Chinese machines are rated at 20 gauge CRS (Cold Rolled Steel), which MAY let you go up to 18 or 16 gauge aluminum (or it may not...they are a little liberal with their ratings), but would likely NOT stretch all the way up to 12 gauge with aluminum. The new Baileigh combo machine is rated at 16ga CRS, which the manual SAYS means that it could do up to 10ga aluminum, I'll let you know when it arrives and I get it set up (but it is listed as a $2K machine).
I did a quick review of Grizzly's site (also sells similar Chinese tools to the one you showed)...
The 12" plate shear, for $125, which appears to be more than heavy enough for your uses (my working definition for 'plate vs. sheet' is: It is called sheet if you measure it in gauge, it is called plate if you measure it in fractional inches)...
http://www.grizzly.com/outlet/Plate-Shear-12-/T23123
I use a table saw to cut all the way up through 1/4" ALUMINUM plate all the time (do NOT do this with steel!!!). I have a regular contractor's 10" table saw, with a non-ferrous blade installed. The cuts are dead straight and need very little cleanup when done...
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View media item 12713I know you said you don't have a table saw, but they are out there all over CL for $50-$100 in my area. Worst case, go to HD and get one for $200.
The non-ferrous blade is VERY easy to find--HD has them for sale for about $60 (the Freud Diablo Non-Ferrous blade--it is also a Laminate Countertop blade, which is also rated for non-ferrous metals). I keep it loaded in my table saw all the time and it does a good job on the simple wood cuts I need too. (you are looking for a triple-chip cut blade, with a thin kerf.)...
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I also keep a non-ferrous blade in my circular saw. I think I use the Onsrud non-ferrous blade in that saw. I also make wood cuts all the time (2x4s, MDF, plywood) with that blade and it works well....
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Use all of the normal safety precautions with table saws. Definitely wear a full face mask, goggles, and long sleeves. The swarf (what you call 'chips,' when working with metal, instead of wood) fly everywhere and they hurt a little on exposed skin (which makes it hard to concentrate on safely cutting the aluminum sheet/plate).
--- Again, DO NOT do this with steel! ---
See my 'cutting aluminum with a table saw' thread here...
http://www.garagejournal.com/forum/showthread.php?t=122619
Like everyone else, I'd like to see what you are working on! Snap a few pics and let us see.
M_P