Originally Posted by
base2
The hole in the downtube is a stress riser in a high stress location. Especially with the cheap single margin drill bits that seems to be the most common available at the local hardware store. A proper double margin drill bit &/or reamer & the proper cogsdill deburring tool would be the proper tools for the job, along with a drill guide to ensure a straight round hole. Expensive city.
Originally Posted by
unterhausen
I am as paranoid as the next guy about breaking wires in this flex situation, but I have a batch of bikes with dyno taillights and I have never had a problem with wire flex getting across from the fork to the frame. I was a little worried about my travel bike since I had never used internal wiring before, but there is no more flex in that setup than there is on the external wiring jobs I have done. Just have to make sure there is enough slack. It just doesn't move that much and the wires I use are stranded and very flexible.
And if it does break, it's easy to replace.
Usually the flex problem is solved by coiling the wire that dangles between the fork crown and the downtube. From the point of view of cable flex it makes no difference whether the cable enters the downtube or it is merely clamp on on the outside of it.
Can either of you recommend a few upgraded tools that a home— (in fact, apartment—) mechanic can buy to make the drilling into the lug as neat as possible? I can spend up to $200-$300, especially if those are tools that I may reuse here and there, whether drilling into stainless steel fenders and racks or making furniture or whatever. Nice cobalt bits (I had never heard of double margin bits but would be happy to see if they are affordable)? A consumer deburring bit set? I understand that your professional conscience tells you I should just not do it. But we are talking about a <5mm hole in a couple of <$300 frames for my personal use, and I am a <150lbs rider who does not really do any loaded touring or any crazy log-jumping or anything that would really make a disastrous failure likely. So — any tips you can give me to help me make the job less crappy are welcome. Thanks folks.