Michigan John wrote:
> So, I'm trying to get a quill stem unfrozen from a fork tube. The dude that
> owns the bike bought it from a guy who used it on a trainer and SWEAT all
> over it for years. The headset is shot, so the quill stem has got to come
> out. The quill is aluminum, the threaded fork tube's steel.
>
> I've been soaking it with Liquid Wrench for over a week. Tapping and
> banging. I even heated what I could reach with a propane torch. It's still
> not moving.
>
> What do I do now?
>
>
See:
http://www.sheldonbrown.com/brandt/stuck-stem.html
The problem is that aluminum corrodes and forms oxides which are
bulkier than the parent material, so the stem "swells", locking it in
place. The oxides are relatively impervious to chemical attack and you
can't usually get lubricants into the interface.
You can try to get it to move with a vise, but often the amount of
torque you'd need is more than you can provide without damaging the fork.
The inevitable solution is to cut off most of the stem and start
removing material from the inside of the tube formed by the stem stub.
After you get the wall thinned, you can slot it and fold it away from
the inside of the steerer.
I've only done this once, I used a rotary rasp bit (a pear shaped one on
a hand drill) to chew away the stem wall and a hacksaw blade to slit. I
left enough of the stem above the steerer to grab with pliers. It was a
bit tedious, but all in all took an hour or so.
The reason I used a rasp bit is that grinding stones are slower, tend to
clog with aluminum and can cut the steel steerer. I suppose you could
use successively larger drill bits (if you had them). I found I didn't
have to go that deep into the stem stub (perhaps 1") because the
corrosion forms at the top.
