Project Update: Lugged Carbon Frame

Practical Aspects

A lot has changed. I learned a lot very quickly, and could no longer justify strict adherence to my original plan. It would be chasing the wrong goals.

My original schedule (dates mark completion):

3/6 Mold (70%)

3/13 Composite Testing (started)

3/20 Geometry finalization (DONE!)

3/21 start carbon fiber (plans drawn, waiting on test results)

3/27 finish all steel parts (40%)

4/3 Jig and assembly (methodology designed aka 10%)

The machine shop was a huge unknown, and after researching it, I decided that all machined items take priority. I have no control over the machine shop turnaround. Geometry has been finalized a long time ago, and all machining I can’t realistically do myself in a few afternoons has already been submitted. As those parts come in, they will be fitted and welded. I would like this welding done by the 31st of March.

While these parts are in the pipe at the machine shop, I’m kicking carbon research into full gear. The mold for the front tubes is all done. The first results are absurdly stiff and strong. They are however, marred by bubbled and incomplete lamination. I found that this lamination is strongly temperature dependent and the next generation of carbon will be out tomorrow. They will both be destructively tested. If I am satisfied with the results, testing can be considered more than half way done.

The mold for the rear tubes will be done in a matter of days.  I think it will be done tonight, in fact. Stretch goals. That would put “mold” at 100%

If I can converge on an acceptable carbon process within a week, the tubes can be done by the beginning of April.

My estimates put the project at more than half way done. The project is fully understood (excluding unknown unknowns). My jig design is very simple and accommodating of tolerance. I have prior experience in brazing, so once machined parts are in and fitted, that should be a couple nights. Carbon testing is mostly hurry up and wait, giving me time to pipeline other tasks.

That all said, worst case estimates are all component parts by the end of the first week of April, leaving assembly. Maneuverability will be known as parts come in because they will be jigged, averting risk of misfitting parts. Risk is further mitigated with hand files and dremel tools.

Aesthetic Change

I’m strongly tempted to change my aesthetic. Fortunately, this doesn’t have to by done until the end, but I have an idea that I think will look way cooler, and in some ways may be easier to make (though probably not).

I want to go from 90s to something sleeker. I’ve always liked the look of carbon fiber. It’s almost synonymous with advanced technology. I’m pretty invested in this, and I like black.

In juxtaposition with this advanced material, I’ve always liked these:

There is a very classic, rustic look to the walnut stock and the blued steel. It’s timeless, and sends the message of strength and quality. Something like this conjures the image of a family heirloom, and of tradition.

I want this as my new aesthetic. To merge this 1800s image of quality and craftsmanship with the 2010s image of quality and craftsmanship. The steel lugs will be oil blued, which should offer a stark contrast with the brass brazed junctions at each angle. By bluing the ends of each lug at a higher temperature, the yellow at each junction can fade to blue, and then to black as it transitions into the carbon fiber tubing.

My analysis indicates two more interesting things. First, that the seat tube does not bear that much load. Secondly, that walnut, the choice material of gun stocks, is more than strong enough and impact resistant enough. Because my manufacturing process restricts my ability to join my seat tube lugs with a long piece of carbon fiber, I want to instead accent the blued steel in this area with a small piece of treated walnut dowel.

I want this bike to be the steed of an iconoclastic cowboy.


It works:

Torch bluing
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3 Comments. Leave new

  • […] Project Update: Lugged Carbon Frame […]

  • Andre Szlendak
    May 2, 2016 6:30 pm

    Great job adjusting your schedule to keep it realistic but also accounting for current unforeseen circumstances. I offered to help with the welding, but this is probably a little more technical than I’m able to produce. Let me know if you have any other projects/ideas that you might need help with.

  • Sreyas Krishnan
    March 20, 2016 11:13 pm

    Gahhh your pics aren’t showing up for me! Forever on the edge of my seat waiting to see your progress haha.
    I’m a big fan of the blue steel look (the one from zoolander too) and I’m really interested to see how it plays with the black carbon fiber. I’m also really interested to see whether you’ll be able to get that same glossy finish on the carbon fiber externally that you are currently getting internally. If both of those things work out, you might be onto something big time with this project…even beyond this course!


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