Originally Posted by 3alarmer

.
...you can make a tool out of a sacrificial screwdriver, grinding/filing the tip to match the end of the purpose built tool. But I've never had much trouble using the tool, as sold, the proper sized hex key on the other side, and a liberal amount of ATF/acetone mix. I usually end up doing this operation sitting down at the kitchen table, which has tiles on top, over which I place some newspaper. That way you can kind of push down on the chainring tool on the bottom, using the hex key on the top.