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 wedge 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 <email@example.com> 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