Wayne Bingham wrote:
>
(cut)
> I would agree that the crank arm in question does, indeed, look to have
> a crack, and I would also agree with Mark on his corrective measures.
> I've done the very same thing several times, and I use almost the exact
> same method. The only difference is that I use various shapes of
> jeweler's files, but the rest of the process is pretty much the same. A
> Dremel tool with a polishing wheel works for polishing it out
> completely, if you really want to take it that far (I usually don't).
> I'm about to do the process again on a crank arm intended for another
> project. I'll have no qualms about riding it, but I don't anticipate
> that the crank will see a lot of new miles either. I've also done the
> process on "rider" cranks prior to any evidence of cracking, just as a
> preventative measure. In those cases, since there is no existing crack
> to file out, I just slightly smooth out and "soften" the problem area.
> I've never witnessed further cracking on "modified" arms.
>
> Of course, I'm not offering any guarantees here, either!
I would add that it was common practice among race mechanics in the 1970s to file the "problem area" (the web) on brand new Campagnolo cranks. Also, it was accepted that there was a possibility that parts would occasionally break with dire consequences. Of course, this was in a more innocent time before the epidemic of lawsuits/lawyers.
Chuck Schmidt
South Pasadena, Southern California