I love quality tools, especially tools that are purpose-made. For the monster fan pulley nut I’ve been using my Knipex parallel jaw pliers because a proper size wrench is too thick to fit Recently, I found this gem on eBay. A guy that works as a machinist in a restoration shop made these. It’s a CNC’d steel wrench, Cad or perhaps Zinc plated steel. Has a 1/2” socket hole for a ratchet or breaker bar. A nice piece, and at $45 including postage, a deal.