the best tool i have found for getting stripped allen heads out is called
"sock-it out" they don't have a website as far as i know.  they are
available at your local machine tool provider or J&L industrial supply
which is where i bought mine.  i went and bought them after all the normal
tricks like fractional allen drivers and torx bits failed.

here is an industrial publication that talks about sock-it out and other
broken fastner removal techniques.

http://www.metalartspress.com/Removing%20Frozen%20or%20Broken%20Taps%20and%20Fasteners.pdf

and the website for j&L tools offering of this tool
http://www.jlindustrial.com/catalog/product.jsp?id=SOC-01000J&origin=SEARCH:KEYWORD&backtosearchpage=Y

jonathan

On Sat, 14 Oct 2006, Evan Mac Donald wrote:

> This isn't about the pulley removal, but instead goes to the reason the
pulley had to come off.
>
>  I have found that Torx drivers are good for removing stripped allen
bolts. The oh-so-common 6mm can be removed with a T-45 bit, driven home
(gently) with a hammer. Once the Torx bit is set in the stripped-out
allen, it can be taken out just as normal. This requires no better access
to the "dead" bolt than usual, and also requires no drilling or use of
Easy-Outs. Great!
>
>
>