Bicycle Fixation Weblog
[Previous entry: "Knicker Knews Knumber 8"] [Next entry: "More Hot Air on Hot Air"]
10/27/2006: "Vivian the Plated Bicycle Will Ride Again"
A few weeks ago I received an email from a reader, Gary P, who sent his sympathies, encouragement, and an interesting idea. (Let me add that I have received emails, both sympathetic and technically helpful, from readers from all over. Thanks, to each of you. You all rock.)
Gary wrote, "Ask Steve Thompson if he would turn for you two 17-4 alloy stainless steel rings that will be .002 in. smaller on the inside than the head tube lugs are in their outside diameter. To install them, heat them up and they will expand, then fit them in place on your frame over the top and bottom of your head tube. They will shrink when they cool and fit as tight as a drum."
Meanwhile, Steve Thompson called. He, too, had heard about Vivian's misfortune and insisted that we let him try to help. So we scheduled some time and I arrived with Vivian (the bicycle), Rick, Gary's good idea, and some hope.
At this point my determination to find the root cause, to point a finger at someone or something is completely gone. Answering a question is one thing, but playing the blame game is never productive.
For an hour we discussed Vivian's condition and reviewed our options. Several short, hairline cracks were evident at the head tube top, but to our surprise, they weren't all in the frame. At Steve's very close inspection he found that the inside of the tube was at least partially plated. This wasn't evident by merely peering into the dim tube. Un-burnished, the plating inside the dim pipe looked like clean metal. This means that some of these cracks were in the plating, not the frame. This also underscores my earlier advice to either mask the frame yourself, or review the masking needs with your plater. Every crack in the plating is another way for corrosion to get in.
Still, the question of what to do remained. Gary's idea agreed with Steve quite a bit, who deemed it "very good ." But it turned out that Vivian's head tube lugs had either flared, or were designed to flare, at the openings, making it impossible to fit rings small enough for a tight press. Welding the tube was also out of the question. The trouble of stripping, welding, grinding and re plating was just too arduous and costly with no guarantee of keeping any kind of esthetic integrity.
Since we couldn't strengthen the broken tube, we had to turn to the headset, and the source of the cracking: outward pressure on the tube. Steve decided to relieve some of the pressure by taking 1 to 2 thousands of an inch off the headset at the press fits, and using Loctite Bearing Retainer Fluid to improve the hold. The fit would be just tight enough to hold and no more. This will relieve the stress on the tube, preventing (somewhat) the cracks from getting worse. Though it meant that the headset would never be used on another bicycle, and that replacing it down the line would be difficult, we felt that the solution would extend Vivian's life to make it worthwhile. Not a perfect solution, but the best one under the circumstance. But, if everything went well, she could be built-up that evening.
Everything went smoothly, and two hours later we were back home with Vivian in the living room, looking out the window at a better future.
