On Thursday, March 22, 2018 at 10:31:15 PM UTC-6, Dave Small wrote: > > I've been out on a 6-day tour and mostly offline, and got home today to > the Blug and this 128-post (as I type) string. I've just read through 'em > all and Scott is the only one who's broached the thing I latched onto when > I read the Blug: What is a "combo tig-fillet BB shell?" Does anyone know? > I'm as happy with fillet-brazed as I am with lugged, but I'm not enamored > with TIG. > >> >> Dave,
I don't think there's any mystery here. Sounds like the bb shell will be tigged in. As others noted, this would eliminate having to have different castings for *each* frame size. Otherwise, each wheel size would have a different drop dimension and, even in frames with the same wheel size, proportional chainstay lengths would require the angle of the sockets to be different in to maintain that drop dimension. And the downtube angles are different on each frame size anyway. It also allows them to ovalize or baseball-batt the bottom of the seat tube as the Blug description alludes to, and like the Roadini did. I don't know enough to understand the benefit of that - whether it ends up being stronger by increasing weld length, or if it's easier because it eliminates some tricky copes, or both. The rear dropouts are similar. BUT.... When done, they will go to the expense and trouble of covering those tig welds with a fillet, making them both stronger and more beautiful than a lugged shell! As I mentioned above, I can't imagine how this would yield a savings from a labor standpoint. It requires more skill, multiple steps, and a third fabrication process. So I assume that the main benefit is that it allows them to get a design to market sooner, with more design flexibility. The only downside I can see is that it would be hard to replace a damaged tube in the event of an accident. But how often does that happen in practice? Rivendells are lifetime frames for most people, but I'm still guessing that replace-ability is usually more of a theoretical benefit. -- 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 post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
