Fillet brazed steel bikes, handcrafted in Oklahoma.

Cleo’s 29er

Now I’m starting the much awaited mountain frame for Cleo. It’ll be here first actual new mountain bike in 20+ years of riding. It’s also going to be my first bi-laminate bike. Bi-laminate construction is a combination of lugged and fillet brazed joints. It’s a pretty time consuming process, as the frame joints are basically done twice. You’ve got a short piece of tubing brazed to the adjoining tube, with a fancy treatment cut into the other end. A smaller diameter tube is slipped into the stub, and it’s brazed like a lugged joint.  Ritchey Annapurnas were done like this, and they were some of the most expensive and sought after frames of the time.

I’m going to do longer points,

Like that. It starts out as a piece of 4130 chromoly tube 1/8″ larger than the frame tube itself. In this case, the sleeve is cut out of 1 3/8″  with a wall thickness of .058″. That gives you an inside diameter of 1.259″, which is .009″ larger than the down tube. That .009″ doesn’t sound like much, and it isn’t. It’s just enough room for the brass to wick into when you braze them together. Since the sleeve doesn’t need to be that thick, I turned it down on the outside, from .058″ to about .030″. It’ll look a lot better, and it will still have the right dimension inside.

That’s the sleeve slipped over the tube to see how it looks.

Add flux

Add heat

Add brazing rodIt looks pretty burnt, but the flux starts off grey so it looks worse than it is. This is some new stuff I’m trying out, and so far I like it except that the flux is harder to get off after brazing. The Gasflux stuff I’ve been using comes off pretty good with hot water, but this has to soak for a while and seems to require a bit of elbow grease. Not the end of the world, but I like time savers. Once the sleeves are brazed on the tube ends, I’ll just build the bike like a normal fillet brazed bike. The other option is to braze the sleeves onto the head tube and proceed like you’re building a bike with regular lugs, like this example.

That one’s not my work,  it’s a pic from the Flickr page of Engin Cycles. Anyway, that’s it for today. You can probably expect more timely updates, as I’m trying to get some progress made on hers and a few others.

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7 responses

  1. Is the “lug” pieces allow you to use thinner tubes, or are they purely cosmetic? Very cool post, by the way.

    January 25, 2010 at 6:00 pm

    • edoz

      The decision to do it this way was based on cosmetics. I’m using the same tubes I would use without the sleeves, but it does add a good bit of reinforcement to a highly stressed area.

      January 25, 2010 at 6:56 pm

  2. jason

    are you going to start wearing your girlfriends pants when you are done with her bike? I never would have thought Tulsa would have a hipster frame builder.

    January 26, 2010 at 6:25 am

  3. edozbicycles

    Yeah, cause the Tom Ritchey influence and geared off road bikes are hipster staples. Oh, wait….

    Looks like I’d better keep my pants.

    January 26, 2010 at 1:10 pm

  4. Herb Wright

    Are you doing this at every joint or just the ones on the main triangle?

    January 27, 2010 at 12:06 pm

    • edozbicycles

      The head tube joints and seat cluster are getting this treatment. The seastays are the two piece design you saw before, and I’m doing plain fillets around the bb.

      January 27, 2010 at 5:36 pm

  5. Brian

    Holy crap, I love it. I’m in line for a road bike, right? ‘Cause that’s what I want on it.

    Looks great! Cleo deserves a trophy like this!

    January 29, 2010 at 6:24 am

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