Originally Posted by
mikeread
Would I be right in thinking the following ?
If the OP had tacked the whole main triangle before brazing the ST/DT joint, the joint would try to close up (as before) but being restricted from doing so, would put a 'hidden stress' into the structure.
If this is the case, then if the OP forced his misaligned tubes to fit as intended and finished up the frame, would it give the same 'hidden stress' as would be present if he had tacked the whole lot together first?
Part of the way to reduce internal stress is to spot, align and braze in a way that doesn't create it. There is a lot that goes into brazing a joint the most effective way possible including what size tip to choose and the heat pattern one follows. The heat from brazing will always create distortion and it is the job of the builder to know how to minimize its effects.