Thursday, October 13, 2005

Mafac Rack Attack

So, the faithful reader knows that frame 090105 uses old Mafac centerpull brakes. The cons: hard to fit/adjust (or at least hard to maintain the fit while tightening up the bolts); brake squeal when stopping. The pros: powerful brakes; easy to modulate; light weight (say Record or Dura Space level). I just discovered another con last night.

After mounting the rack (80% done) to the fork, I installed a brake on the fork to fit a rack support that would connect to the brake-bolt and snake under and around the brake to reach the rack. Installed is incorrect. I tried to install the brake. It turns out that the brake extends so low, and so wide, that it interferes with rack and vice-versa.

So, despite having redone the one rack leg - its time to take the legs off again. Urgh!!!

For a long time, I've been looking for an excuse to move the rack eyes from the front of the fork blades to the sides. In the later config, a hole gets drilled into the fork blade and an H2O nut and reinforcement are brazed in. Because the nut goes through the leg, it is better supported. Plus, it just looks nice.

So, the legs are off the rack - it'll get cleaned up (old flux and silver) tonight. The old rack eyes are off, and the new ones are on. And, I've designed some rack legs which I think will look nice and which will clear the silly Mafacs. I might still get this fork on the bike for Saturday.

Along the way, I found it takes a lot of heat from the torch to adversely affect the paint. When it does - the paint becomes really noxious, but I wore my respirator. Anyhow, after I was done, I fiddled with the paint some. Two things, it seems to be less brittle and it definitely has a better bond to the fork. So.... I'm considering a scuff sand of the whole fork, applying primer where I sanded down to fresh metal, allowing this to set overnight, then heating all the paint with the torch in the morning and spraying a new top coat on tomorrow evening. If this leads to more durable paint (probably just a dream) I might go back to the whole frame and apply the same basic process.

Once again, I'm making lots of mistake to learn from.....but hopefully I am learning from them.

Another side lesson, the 3/8"X0.035" stainless tubing is tough stuff. For such a little, light, assembly, it is stiff and strong.

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