Originally Posted by
guy153
I've "reamed" HTs with emery cloth wrapped around an aluminium drum with a slot in it run in a drill. A bit redneck but so long as you get a good fit without the cup spinning that's all you really need. But I'm sure your milling will be more ideal.
I used a similar method on the seat tube. 120 grit on a 1/2" rat tail file, but didn't need to remove much material... Not elegant, but it worked. Agree with Unterhausen, .5 mm is too much to remove with sandpaper!