So I have a threaded headset with a quill stem on an old road bike. I was getting a little bit of a grind when turning so I opened it up to take a look at the headset. A long story short, no matter how much I tighten the bolt on the stem I cannot get the handbars/stem to hold firm with the fork (ie. a bump to the wheel will cause it to become misaligned). Does anyone have an idea about what's going on and what I can do to fix it?
See if the bolt turns freely wedge/plug at the bottom of the stem. Is it binding? Is the bolt too long making the wedge/plug hit the end of the unthreaded part of the bolt? Is the stem a good fit for the steerer tube? Is the steerer tube damaged somehow?