And this is that %$^#*! screw.
This is the shuttle assembly. I have the machine set at the widest zig zag. This is the needle at its lowest point and to the far right of its path. The hook (pointy part) of the shuttle should be almost touching the needle. Note the rather large gap.
I will send the husbeast to the local Sears dis-Service Center to try to locate and purchase that special pentahead socket. I don't hold out much hope as they are generally clueless. I may have to try and butter up an OSMG (old sewing machine guy) and get him to either sell or loan one.