Fwd: [CR]Sanding down a stem to fit 22.0 a la Sheldon Brown


Example: Component Manufacturers:Cinelli

To: classicrendezvous@bikelist.org
From: Bianca Pratorius <biankita@comcast.net>
Subject: Fwd: [CR]Sanding down a stem to fit 22.0 a la Sheldon Brown
Date: Fri, 22 Feb 2008 15:56:09 -0500


Begin forwarded message:
> From: Bianca Pratorius <biankita@comcast.net>
> Date: February 22, 2008 1:42:21 PM EST
> To: Thomas Adams <thomasthomasa@yahoo.com>
> Subject: Re: [CR]Sanding down a stem to fit 22.0 a la Sheldon Brown
>
> I made a mistake. I was looking at a expander cone type stem. I
> measured at the very tip of the stem where the cone presses. At this
> spot the stem walls thin to only 1.0 mm but you are right... at a spot
> even an inch farther up the stem walls are much thicker. However if I
> sand a stem I'll have to sand the thin edge too. So, I'm taking your
> advise and only using a sliding wedge not an expander cone stem.
>
> Garth Libre in Miami Fl USA
> On Feb 22, 2008, at 10:04 AM, Thomas Adams wrote:
>
>> Dear Garth:
>>  
>> I've done it twice, with no problems.  As I weigh 235+ lbs, it seems
>> pretty safe.  I'd try to use a stem with a sliding wedge instead of a
>> split end/expander cone (the Cinelli style) as they are supposed to
>> be stronger. Just make sure before you start that the sliding wed ge
>> fits inside the steerer.  BTW, I'm not sure how you figured that
>> you're losing 1/5 of your material, but if .2mm is one fifth of the
>> stem, then your stem shaft has walls only 1 mm thick.  Most of the
>> ones I see are more like 1-2 cm thick, making the .2mm 1/500 or
>> 1/1000 of the wall thickness, if my math is correct.
>>  
>> BTW, when you do the sanding, be sure to pull the expander and stuff
>> paper into the shaft.  Otherwise you spend a very long time cleaning
>> aluminum dust off the expander and the inside of the stem.   
>>  
>> Tom (fractionally challenged) Adams
>> Manhattan, KS
>>
>> Bianca Pratorius <biankita@comcast.net> wrote:
>>> On Mr. Brown's web site he mentions that you can usually sand down a
>>> stem's quill to eliminate .2 mm of aluminum. He doesn't seem
>>> concerned
>>> that that would mean eliminating 1/5th of the metal at the expander
>>> bolt to accomplish it (by my estimation). Has anyone done this with
>>> good results? (Not causing a dangerous crash from home spun
>>> re-engineering. I have a stem that would go nicely on my French
>>> headset
>>> and I might try this if the list thinks it's not too awfully
>>> dangerous.
>>>
>>> Garth Libre in Miami Fl USA