I have made a tool by grinding that engages the slots and can can fit in a vice. Then you can bear down on the crank so the tool remains engaged in the slot while turning the allen key.
Another thing to try is the Sugino tool that is like the Campy. It may work better since it has a section which engages the center of the allen bolt to keep the tool slightly more stable.
Joe
--On Tuesday, January 09, 2001, 10:23 AM -0500 Tom Hayes
<hayesbikes@nls.net> wrote:
> I have a chainring bolt, campagnolo, that I have so far be unable to get
> off the crank. It is holding (the remaining one) two NR chainrings
> mounted to a GS crankarm, if that makes any difference.
>
> I have used the appropriate Campagnolo took with the little prongs; one of
> the backside slots is now slighly mangled. The bolt and fastner keeps
> turning together, and I cannot find a tool, or any other device--already
> tried a large screwdriver-- that will fit the slots that I can hold
> sufficently tight to loosen the screw with the hex wrench. I've tried
> needle nose pliers holding the backside, used enough liquid wrench. I've
> exhausted my limited understanding of tools and bankrupted my equally
> limited imagination for devising something that would work.
>
> Any help out there.
>
> Thanks.
>
> Tom
> Tom Hayes
> 18585 Munn Road
> Chagrin Falls, Ohio 44023
> hayes@jcu.edu