Thursday, May 19, 2011

Another big cross bike

While I'm waiting for acetylene to finish up Dave's cross frame, I started working the lugs, BB, and dropouts for Josh's cross frame. It's another frame over 60 cm. These big bikes are getting to be the norm around here! Pretty cool.

When I say "working the lugs", basically what that means is grinding and filing the lugs to get all of the fits just right so as to promote proper alignment, have the appropriate brazing clearances, and have the look I'm after. If there are tight spots between the tubes and lugs, you may get an area where the silver doesn't flow into it. On the flip side, you don't want an area where the gap is too large because the silver doesn't fill gaps well and you really don't want it to serve that purpose. The first thing I do is focus on working my lug and BB sockets. I want everything to sit nicely in the jig with no force or stress. That usually means bending the lugs a bit to set the angles. Then I start grinding and filing the lug ID so that the tubes slip in without any extra movement. That's where I'm at with this frame. Next steps will be to finish the shorelines of the lugs and filing the outer surface of the lugs to make them look the way I want. And then we'll see a mean cross racing machine start coming together.


davids said...

Thanks for the explanation of what you're doing here.

The frame looks amazingly well-proportioned - I know how big its owner is! Beautiful.

davros said...

beautiful work