As a newb and a hobbyist, i climb the learning curve mistake after mistake. My current project (29er fillet brazed, Zona) is a good example. So long story short, here is the problem : after tacking the front triangle came out absolutely straight from the jig according to my alignement table.

DSC_0057.JPG

HT to ST was also still OK (less than 1 mm over 1m) after fillet brazing, so i did the finish work and got ready for the next step. This said, i noticed during the prep of the stays that the front triangle was not seating really well on the jig, so i went back to the alignement table to not only recheck that the HT was parallel to the ST (which i normally do as per previous pic with 2 cones and a 1m rod), but also that HT/ST/BB were in the same plane (this for some strange reason I rarely do, assuming that the HT would be in the right place...). And obviously they are not : it turns out that the entire HT is nearly 4mm off center to the drive side

DSC_0070.JPG

At this stage, cold-setting would be insane. Leaving the front triangle as it is would also be a bad choice given the importance of misalignement. And in that case, what would be the next step : brazing the rear end in the plane of the BB (meaning twisted cranks), or in the plane of th ST/HT (meaning twisted....I don't really know how twisty this would be) ? I was close to scrap and redo (i actually ordered a new set of tubes at Ceeway already) but then i remembered reading that some guys re-aligned tubes only with heat.

I clamped the frame to the table, and slowly put heat at different spots between the braze-ons until the frame got back to normal. No flux as i wanted to see what i was doing. Heat until red shows up only. 3 spots. Those spots are easily visible here

DSC_0073.JPG

And the result:

DSC_0072.JPG


So my question to you guys : should i continue with this frame and go to the rear end now (needless to say that this bike will be mine), or should i assume that the structure of the front triangle has been so damaged that it should be scrapped ?

Thanks for your inputs

Christophe

PS : Dave Bohm already told me to work per quadrants to control the distorsion. I totally get that of course but need to practice more