Originally Posted by Doug Fattic

Rizaa, let me give you a bit more information on steel frame alignment and cold setting. I'm a framebuilder and painter that has aligned hundreds of frames in my long career. I would be surprised if your frame is perfectly aligned. My experience has shown that the majority of steel frame leave the factory or shop somewhat out of true. The exceptions would be some Japanese frames and expensive custom frames. And if a frame is well used something in its history makes it worse. The heat involved in brazing or tig welding pulls the tubes in the direction of wherever the heat is applied. It is the skill of the builder that everything ends up in plane and the dropouts equidistant from that plane. Usually this involves many little cold sets during the build. Because it requires extra time and effort to get it spot on, most frames are usually not. It is a myth that cold setting hurts a frame. For example forks are bent a lot to get its curve.

Properly aligning a frame is not a simple task and requires special tools. Professional builders will have some kind of big accurate surface plate as a foundation to check alignment. This piece of equipment would be very rare in an ordinary bicycle shop. The process starts by taping and facing the bottom bracket shell. Then the frame is attached to the surface plate and each tube is checked to see that it is parallel to the table. It is especially important that the seat tube be 90º to the threads in the BB shell because if it is not, that can put can twist the flats of your pedals putting a strain on your knees. Next the dropouts are checked and adjusted so their inside surface is equidistant from the center of the frame. There are a variety of tools that can check that. Then dropout alignment tools are used to bend the faces parallel to each other and a rear derailleur hanger tool makes sure the derailleur hanger is square with a wheel. After all that adjustment the entire frame should be checked to make sure everything is still right. I don't know any of my colleagues that charge as little as $30 to do a full alignment.

As others have already mentioned, I commonly spread 120 5 speed spacing to 126 6 speed spacing back in the early 80's. When 130 became the standard for 8 speeds (and more) than I was often asked to spread 126 to 130. You would have to look very close to notice any tiny amount of bend in the stays.