A comprehensive educational community devoted to trim carpentry, finish carpentry and architectural millwork. Hosted by nationally recognized author and finish carpentry specialist Gary M. Katz.
  a homemade brake  
You can make one of these light-weight, small footprint brakes without a lot of effort. They're handy for installing exterior trim on columns and small projects, and for bending step-flashings, etc.
I've made a few of these. The first one's weren't nearly as effective. Piano hinges work well for attaching the lid (the lid has the handle on it). In the illustration below, I've shown a piano hinge securing the lever to the base, too (the lever is the front board, that you lift for bending metal), but a pair of butt hinges works just as well (see photos below). By removing the pins from the butt hinges, the front lever can disconnected, which makes it easier to store this otherwise awkward contraption.
Mike Guertin suggested I add a metal blade to the brake. I did that recently, and it improved the sharpness of the bend, and the bite of the lid: now, with the lid clamped down, the stock doesn't slide back.
Most of the metal I install needs a drip edge, which I bend first. I drew a line on the base, about 1/4 in. from the blade, so it's faster to line up the metal.
Home-made brakes aren't nearly as strong or durable as a full-size metal brake. Bending the small 1/4 in. drip edge puts more pressure on the brake because there's less leverage. I clamp the lid down with the toggle clamps, but I also hold one hand on the handle and press down on the metal to stop it from sliding back under the lid.
The metal blade is fastened with three screws, in slightly elongated holes, so the blade can be adjusted tight against the base, just in case the lid isn't perfectly flat.
I draw a line on the face of the lever, too, so it's easy to line up the stock for the second bend.
Be sure to sand the back of the lever smooth, so the drip edge will slide up as you lift the lever and bend the metal.
Without a brake, a carpenter can't install proper flashings. Stock lengths of L-metal, purchased from a lumberyard, are never exactly the size you need on a jobsite. Instead of giving up and using caulking rather than flashing, take a few minutes to build a brake and your exterior trim will last decades longer.
  Supported by corporations who care about education in the construction industry.  
  Mastering FInish Carpentry DVDs