This is what I made about 20 years back, http://www.tackleund...__fromsearch__1
It's pretty 'agracultural' I know but it worked on sheet Lexan, Brass, and Aluminium (or whatever you guys call it), it cut and bent 20mm circular blanks - If you want standard tapered lips just cut the sides off-- Over the years I have seen a lot of these on forums, going back to the 60's (1960's), from a small ones like mine to larger ones that will cut conventional and 'coffin' lips,, no hydraulics or windmills needed , just manpower, a longer handle and some muscle, you can knock out a 100 an hour no problem. If the tolerances are close this stuff shears like tin foil.!!!
Cheap as chips to make too.
Pete