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5.16 Frame Building Part 4: Lots of little steps...




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This article is from the Misc Bicycles FAQs, by various authors.

5.16 Frame Building Part 4: Lots of little steps...

The hole for the brake bolt on the fork was drilled for us. I believe
it also involved several bits - a smaller one on the front for the bolt
diameter and a larger one for the bolt head to rest in on the back. I'm
sure a substantial leveling process went into this as well since an
brake bolt that isn't straight can be annoying.

After the brazing of the seatstay/seat tube junction at the end of the
third class, the seat tube needed to be reamed again as it was before.

Now that all brazing near the bottom bracket was finished, it needed to
be faced similar to what was done with the head tube. Facing is
creating a smooth surface which the bottom bracket cups can fit against.
Ideally a bottom bracket should be 68mm (or 73mm for some mountain
bikes). Ron said most come from the casters at just over 68mm and thus
provide a little to shave off, splitting the difference on either side.
Mine was almost exactly 68mm to begin with so very little would be taken
off. This was another Campy tool. On one end was a handle and blade
which fit onto one side of the bottom bracket shell. On the other side,
a cut fit against the edge of the bottom bracket shell, then a spring
for tension, spaces, and finally the last bolt. The blade only went
around a couple times in clockwise manner on each side and then taken
out.

All the brazing in the bottom bracket had allowed brass and silver to
get into the threads of the bottom bracket. Another nice Campy tool.
Since bottom brackets have reverse threads on the left side, you have to
make sure this one goes into the correct way. Each side had a threader
which will remove any stuff from between the threads. Both sides are
threaded on, holding each other in place. First one side is threaded
until just a couple threads of the tool are left outside the shell and
then backed off. Then the other side is threaded in until just a couple
threads of the tools are left outside the shell and then backed off. A
pretty simple process.


 

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