So I have an interesting issue, and I have been trying to diagnose the problem. I have a 1" threaded fork that used to have a quill stem. Well, one day, the entire stem slipped out and it would fail to retighten (even at various insertion points). So I thought okay, I'll pick up a new quill stem.
I ended up getting a great deal on a 1" to 1 1/8" quill adapter and Salsa stem, and another issue arises - since my bike is tiny (48cm), the headtube is small and it seems as if the quill adapter doesn't fit in to the "Minimum Insertion Line," - it's about one inch over. However, I changed the wedge at the bottom to a smaller wedge from my old stem and it fit almost all the way in - about 1cm over the line.
However, it still became loose when it was inserted all the way in. So I used the fatter wedge, and now the stem is inserted 1 inch above the "Minimum Insertion Line." BUT, the stem doesn't seem to be moving, and I grabbed the front wheel between my legs and tried to turn the handlebars/stem, and it didn't budge. However, I don't know if this will last, and who knows if it'll just fall out again.
So what should I do? Take it to a LBS and have them take a look, and regrease? I'm aware that I shouldn't put the stem in TOO far, like in Sheldon Brown's advice. I'm wondering if that was the case when I had the stem inserted to the line, but it still came out.