Not crying or feeling sorry for myself but this incident is new to me and I thought I'd share. I always use the heat/wax/cool method with studs and had a top-center one crackle and snap at about half of the expected breakaway torque. It broke three threads below the surface and the remains inside the block has a dark spot in the metal somewhat off-center. To me it looks like an impurity in the metal. I guess sometimes stuff happens....to me.
Lonnie
Lonnie