J
Russell Seaton writes:
>>>> The problem is not stem failure but rather permanent stem
>>>> attachment when the aluminum corrodes and often does so enough to
>>>> put a bulge in the steer tube.
>>> But can't this be easily eliminated by just undoing the quill bolt
>>> in your quill stem once a year with a 6mm Allen key and getting a
>>> stick of wood and smacking the top of the Allen key to loosen the
>>> cone or wedge in the fork steerer.
>> I think what Brandt is saying is that over time when inserting the
>> quill stem at the same depth in the steering column, a bulge could
>> occur over time. I have heard of this happening, but never seen a
>> column with a bulge. To me, one would have to really torque the
>> steel wedge or conical cone to get the steel column to distort a
>> bulge. A lot depends on the thickness of the column tubing.
> No. What Mr. Brandt is saying is:
>>>> The problem is not stem failure but rather permanent stem
>>>> attachment when the aluminum corrodes and often does so enough to
>>>> put a bulge in the steer tube.
> Mr. Brandt is talking about corrosion welding the quill stem inside
> the steerer. Eliminated by not allowing the quill to weld inside
> the steerer by just pulling it out once or twice a year and
> re-greasing it. The beginning weld is broken.
There is no welding. The contact is a high pressure interface with
aluminum oxide expanding inside the steertube. Aluminum oxide cannot
be welded to steel. That is why sawing off the stem just above the
steertube, boring it out and breaking through one side with a Dremel
tool releases the pressure fit and the remains pull out easily.
Jobst Brandt
>>>> The problem is not stem failure but rather permanent stem
>>>> attachment when the aluminum corrodes and often does so enough to
>>>> put a bulge in the steer tube.
>>> But can't this be easily eliminated by just undoing the quill bolt
>>> in your quill stem once a year with a 6mm Allen key and getting a
>>> stick of wood and smacking the top of the Allen key to loosen the
>>> cone or wedge in the fork steerer.
>> I think what Brandt is saying is that over time when inserting the
>> quill stem at the same depth in the steering column, a bulge could
>> occur over time. I have heard of this happening, but never seen a
>> column with a bulge. To me, one would have to really torque the
>> steel wedge or conical cone to get the steel column to distort a
>> bulge. A lot depends on the thickness of the column tubing.
> No. What Mr. Brandt is saying is:
>>>> The problem is not stem failure but rather permanent stem
>>>> attachment when the aluminum corrodes and often does so enough to
>>>> put a bulge in the steer tube.
> Mr. Brandt is talking about corrosion welding the quill stem inside
> the steerer. Eliminated by not allowing the quill to weld inside
> the steerer by just pulling it out once or twice a year and
> re-greasing it. The beginning weld is broken.
There is no welding. The contact is a high pressure interface with
aluminum oxide expanding inside the steertube. Aluminum oxide cannot
be welded to steel. That is why sawing off the stem just above the
steertube, boring it out and breaking through one side with a Dremel
tool releases the pressure fit and the remains pull out easily.
Jobst Brandt
