Saturday, January 24, 2009

Shelby "Cadillac" circa 1938, Pt. II

In an earlier post about this same bicycle, I introduced it and mentioned the various influences for the color scheme and paint pattern. This is my artful project, and it was very refreshing after so many projects where the main objective was to make a machine look factory fresh with all the original parts, finishes, and colors. The only objective here was to produce something interesting using influences and parts that were contemporary to the bicycle. I'm posting this little story because I hope it might inspire someone to build a road-worthy mongrel out of a bunch of disused parts.
This project took shape over the cold months of 1998 and '99 from a series of swap-meet finds. It started with the pre-war Shelby frame, which came with a seat post and crank set and a long history of abuse and neglect. Rust was blistering an old coat of grass-green house paint, and the middle frame tube had broken free from the seat tube. Clearly no one would complain about what I might do to this mechanical corpse. The fork was also a pre-war Shelby item, but had come off a girl's bike, so it had a longer steerer tube than would fit in this boy's frame, but I could cut it down to size. The wheels came complete with an old (circa 1940s or '50s) set of Western Auto middleweight tires. Compared to typical balloon tires, middleweight tires are narrower (1.75-inch wide) and run at higher pressure (45 psi), so they roll easily and make for a much faster bike.
I tried to keep the total purchase price as close as I could to $100. Even after the pedals and stem, I wasn't too far over until I had to have those very cool flat handlebars.
The repair work was fairly straight forward. To repair the broken frame, I ground out all of the brass and welded the joint. It wasn't pretty, but it was nothing that some time with a grinder wouldn't fix. The stem was rusty and gouged from crashes and pipe wrenches, but what I couldn't grind or file out I was able to fill with silver solder. A fabricated brass bushing took up the wear in the horizontal pivot of the sprung fork.
Compared to other sprung forks, Shelby's "Shock-Ease" hardly looks like a sprung fork at all because the design hides the spring inside the steerer tube. It's an interesting solution that is visually elegant but not particularly good. To absorb impact, the lower portion of fork moves forward. This action compresses the hidden spring, which returns the fork to its original position, but it's like leaning into a punch. When assembling the contraption, I cinched the spring down nice and tight so there is minimal easing of the shocks. That suits me fine.
The finish on the fasteners is dull chrome. From what I know about electroplating, this is essentially hard chrome applied like decorative chrome but at a higher temperature and amperage. The appearance has a dull sheen like you see on micrometers, and it makes for a very tough surface that wrenches don't mar like they will cadmium or zinc plating. This was the fastener finish used by Norton on its motorcycles from around the late 1930s until the early 1950s, and I thought its understated, function-over-form sophistication suited this project well.
The black-painted wheels and the absence of fenders are meant to give the impression of a light-weight machine built for performance, not glitz. But without fenders, where do you attach the pretty red rear reflector? (Irony intentional.) I tried out some arrangements at the seat-post clamp before settling on hanging it off a fabricated bracket that I attached to one of the original drop-stand pivot holes.
The cranks, sprocket, and seat post are gun blued. The only difficult part of the process is getting the metal clean and smooth enough for the process to work. Rust had already stripped the chrome, and sand blasting, grinding, and sanding took care of the rust. I bought a bottle of gun bluing solution for less than $10 from a gun store. The guy behind the counter (at the gun store) said he had yet to sell gun bluing to a gun owner--only hobbyists buy the stuff. I would have laughed, but I didn't want to make any sudden moves.
I found it can be cheap and fun to make a usable old bicycle from cast-off parts. I even learned some new skills.

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