Here is a video on how to install a threadless stem adaptor.

I have been playing with the idea of getting my old Trek 1000 fitted for me. My Jamis Comet has been pretty comfortable to ride for long distances. But I know my weight is not distributed properly on my Trek 1000.
But the Trek is an older bike (1990 model year) and has a quill stem. But it’s a solid bike with an aluminum frame. Yeah, it only has a 7 cog freewheel, and the shifters are on the downtube. But that is fine. I I can get it fitted, I will still be fine to ride, as opposed to spending $1000 on a new bike. Actually, I might be able to find one on sale for $600. But still.
Anyway, I decided to order a threadless stem adapter. I got it for about $15 including shipping. It’s made by Profile Design.
It seats down into the threaded steerer tube like the quill stem. But the top is like a threadless steerer tube. This way I will be able to use a wide variety of stems. Once I get the threadless stem adapter, and get it installed, I will check into getting a fitting. I will check out a couple different places than where I got my previous fitting.
Installation will be a pain. I will have to remove the handlebar tape to remove the old quill stem. Or I could just cut it off. But I’d to destroy it, in case I want to keep it. But I can always buy some new fancy handlebar tape with a funky design. It will be fun. :)