The next day I started over again and this time changed the drop weight to 57#. I finished the mains and started with the ATW and got to my 2nd cross. As I was taking the string off the drop weight in preparation of the next cross, the string snapped near the FC.
I am baffled. I wonder if the drop weight is set up correctly. The drop weight looks to have the weight set up correctly but am wondering if the markings may be off. Next step may be to get a calibrator...and some Jameson/Ginger Ale.