Are you thinking a press brake?
http://www.northerntool.com/webapp/w..._479830_479830

Capacity is heavily dependent on the shape of the dies and especilly the
width. Narrower gives you a sharper bend at the expense of higher
required tonnage and more die wear.

Most of the shop built units I've seen for a 12 or 20 ton shop press use
heavy wall angle iron. Professional press brake dies are all hardened
tool steel. If you could find a 12" section of old press brake die, that
would be perfect.

Keep in mind that the work needs to be perfectly centered under the
cylinder.

Ignoramus24341 wrote:
I wanted to make a homemade brake for bending small sheet metal
things. (I have a press). I think that the concept is straightforward,
however, I would like to know if there is any sort of a table that
tabulated bending effort per inch of the width of metal being bent,
depending on thickness.

Also, for the dies, would it be more proper to use high speed steel as
opposed to mild steel (for strength).

Thanks

i