Where do I get tool for double pulley?

[jss22]

I want to adjust the fan belt on my 78 SC, but I do not have the pulley tool and the only one I can seem to find is for the single pulley set up. I am sure you know the pulley I am talking about, but to describe a little more it is the one that has two holes along the circumference on the outside of the second (auxiliary) pulley groove. Also, has anyone come up with an alternative to a factory tool in order to hold the pulley steady?

[David]

I made one from 1/4" steel plate, it looks like a spanner with a little barb to fit in the holding hole on the pulley.