Coming soon, another fully lugged, S & S BBC tandem! I've been working on this one for a while, these are pretty much as labor intensive as custom bikes get. I make most of the lugs from scratch, which is as big of a job as building an entire frame. I'm really happy with how quickly this bike has been going together. I've really learned a lot over the years making lugs from scratch. I can honestly say I'm down to about 1/4 the time to fabricate a lug than the first time I tried one of these bikes. Having a new tig really helps on that front. I can jig up the frame with all the lug parts assembled then tig tack the lugs together while they're on the frame. That pretty well assures the lug angles are perfect.
Once they're tacked I take them apart and fillet braze the joint. After that, I carve the points and bore out the ID to fit the tubes perfectly. Having proper machine tools and figuring out a method to bore and mill the lugs after brazing has really helped me too.
I usually install all the S & S couplers in the tubes before I build the frame. Some guys do it after, I prefer before since I have a handy jig that holds the tube in perfect alignment. That makes it really easy. Here's a big boom tube getting a really big coupler 1.75"!
Once I have all the couplers in, tubes mitered, and lugs finished, it's time to assemble and flux. Here's the frame ready for brazing. Just preping the tube ends, fluxing and re-assembling the whole thing in my jig can take a couple hours, but when it's ready to braze, the lugs fit up perfectly and all the tubes are in perfect alignment. You'll note the c-clamp on the head tube to hold the lateral tub lug in place. That lug doesn't wrap around the headtube, so it's needs to be secured for tacking.
I started out with a full container of flux. Here it is after fluxing one frame:
I'll also go through several Oz. of silver on just this main triangle. There's a whole lotta lugs on there. If you click on the full frame pic you'll also see how I do my extended heatubes these days. I pre-braze a sleeve on the headtube, then turn the whole thing down on my lathe to make it match up to the upper headlug. It makes brazing the lug easier later on.
In other news, I haven't been on a bike in over 2 weeks. I don't like that. Gonna try to make it out to the Wirth 'cross race this weekend, hopefully I can get on a bike before then. Otherwise look for me, I'll be the guy cramping up at the back of the B race pack...
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