Originally Posted by Jeff Wills

That's the wrong tool. Right-side BB cups are always very tight, so the wrench requires a closed end to prevent it from spreading open. The correct tool is something like a Park HCW-4, as shown previously: Park Tool Co. » HCW-4 : Crank and Bottom Bracket Wrench : Crank Tools . The adjustable cup requires an HCW-11... and those cups are always a bear to turn. The wrench has very little area to grip. You could try a bunch of washers and a spacer to hold the wrench flat against the cup with the spindle bolt.