Back in the late 70’s or early 80’s (I don’t remember exactly) the New England Cycling Academy (commonly known by its anacronym NECA) came out with a system to align cleats on shoes. They originally developed a system to convert body measurements in a bicycle position. The problem they discovered with their cleat system was that so many steel frames were so badly out of alignment that they couldn’t properly position cleats. The reason cleat position was important (especially in the era before floating cleats) was that improper cleat placement could develop knee problems. And so can out of alignment frames. That lead NECA to come out with a frame alignment system they sold to bicycle stores along with their other goodies. This expensive system lost popularity as steel as a frame material declined. There must be some of these NECA alignment systems gathering dust in bicycle stores somewhere. It is also possible that some bicycle store has an owner that was/is interested in building frames and has the kind of equipment that can properly align frames. It is unlikely that a typical store even has a Park Frame Alignment Gage (a long straight edge with an adjustable pointer) with dropout alignment cups. As has already been mentioned that is the minimum it would take (along with a dropout hanger tool) to properly spread a rear triangle. Along with someone in the store that knows how to use them. Although better shops might.

The best approach is to try and find a framebuilder close by. They will have both the knowledge and experience to do the best job. A variation of a solution already mentioned is to use a 7 speed Shimano freewheel or freehub with a Campy 8 speed shifter system. They both have the same cog spacing.

Here is a picture of one of my alignment tables. I have 2 (this is a cast iron one I brought back from England after learning to build frames there) and an aluminum one so I can teach 2 students how to build frames in the same class. The surface gage in the foreground is for checking main triangle tube alignment. The black tool by the dropouts checks that they are equidistant to the plane of the frame. And the Campy “H” tools (partly hidden behind the black tool) assist in bending dropouts parallel to each other. By the way H tools got their name because in old Campy catalogs, Campy tools were identified by a letter instead of number and their dropout alignment cups just happened to fall on the page between tools G and I. The frame is one I’m making for a nephew. Because this is a frame in progress, the head tube has not been cut to length yet.