My 1981 steel framed bike has no threaded mounts for water bottles. So I'm considering drilling and tapping the seat and down tube on a steel frame (tube walls look about 1/8" thick). Is that as bad of an idea as I'm thinking or is the frame so overbuilt that it's not a problem? Have others done this? I have attached the cages with cheap bolt-on rings but it looks like complete crap ends up working loose as they fit poorly to begin with. I have completely rebuilt this bike from the frame up with new Ultegra/SL parts so just considering upgrading this too.