I did a frame once without gauging. I reasoned that the two sides of the rear frame were pretty much the same, so if I simply pulled each dropout by hand in opposite directions, each side would bend the same amount. It did.
I believe it is important to hold the frame up only by the dropouts so that both sides bend evenly. I found it easiest to let the head tube dangle above my feet.
I got the front part of the dropouts to measure 130mm apart, then used a large crescent wrench to bend the dropouts inward so that they were once again parallel instead of splayed outward. This part was important because the hub would shift around when I pedaled until I did it. I eyeballed the parallelism. It is not safe to just tighten the QR until the dropouts bear squarely on the hub because if it's too tight, you'll ruin your bearings and cones.
Last edited by garage sale GT; 04-06-11 at 08:09 PM.