Some builders did the internal brake cable with a full length tube inside the top tube. To my knowledge, this is always done before the top tube is brazed into the bike, as having both ends of the top tube open makes installing the internal tube quite a bit easier. I can imagine a method of doing it after the frame is already built, but I honestly don't know if it would work.
The "standard" way does not include a full length internal tube. Two holes are drilled and after the bit breaks through the drill motor is progressively angled to make a smooth ovalized entrance for the housing. Then short lengths of brass or copper tube are silver brazed into place and the bit that sticks out is then carefully filed flush. This is much easier to do than the full length tubing, and is normally done after the frame is completed, but does make getting the housing through the frame more difficult. Either way, the appropriate tubing is available from Nova Cycle Supply
Doing the derailleur cables is pretty simple, as they are just drilled and ovalized/angled holes in the appropriate spots. The only trick is ensuring that the holes are in exactly
the right place so as to avoid adding extra friction to the cable run. The problem is installing the cables after you are finished: in my experience this is a time-sucking nightmare.
Last edited by Six jours; 03-23-09 at 09:44 PM.