Amateur framebuilder here... Id drill a hole to stop the propagation of the crack then TIG weld to fuse the crack. grind smooth to finish. I would try that first before replacing the whole seat lug.
"If my understanding of frame construction is correct, that also means the top of the seat tube is cracked, since it extends through the seat lug and is cut off even with the top of the lug." Some seat lugs are like that, many lugs used in production have a shelf on the inside where the seat tube would be cut at 90deg then inserted into the lug. (image from torch and file <https://www.torchandfile.com/thumbnail.asp?file=https://www.torchandfile.com/cdn-cgi/image/quality%3D85/assets/images/stl004.JPG&maxx=300&maxy=0>) I believe that is how the lug is on the QB, I can check mine when i get home and report back. Are you at U Michigan? If so, there's Doug Fattic (Niles, MI) and Franklin Frames (Newark, OH?) that are closeish. Doug is great, I don't have experience with Franklin but have heard he is willing to take on odd jobs. Long live the Quickbeam! Christian Phoenix AZ On Wednesday, January 24, 2024 at 10:53:29 AM UTC-7 George Schick wrote: > Are you the original owner of this Quickbeam or did you buy it used from > someone? If the latter is true it may be that the wrong diameter seat post > was initially used and thus the seat post binder bolt over tightened to > accommodate. > > On Wednesday, January 24, 2024 at 1:07:41 AM UTC-6 eil...@umich.edu wrote: > >> Hello, >> >> I am seeking information about what looks to be a small crack in the seat >> lug of an orange Quickbeam. The reason I think it’s a crack in the lug and >> not just the paint is that it is visible from both inside and outside the >> seat tube. Pictures attached below. >> >> Some questions I have are: >> - Am I diagnosing this correctly as a cracked seat lug? >> - Is a crack this size and in this location a big deal (I’m assuming >> yes), and if so, how big of a deal? >> - Does this render the frame dangerous to ride? >> - Can something like this be repaired? Is there anyone that’s had >> something similar repaired who can share their experience? >> >> Thank you for any information anyone can share or point me toward. >> >> Logan >> >> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/72de926f-e62d-4aa9-8b65-4ad19113fe9an%40googlegroups.com.
