We've probably all seen defects in metal but this takes the cake. It's a bar of mystery metal that I was making a temporary arbor with. As I was approaching final size, a crack appeared. It got bigger and bigger until the part dropped off. And when I looked, it was flame cut. Inside the bar!
Originally two parts welded together - probably Vee'd out to increase weld penetration - and you've now turned down to smaller than the penetration of the weld.
Bingo! They must've turned off the weld and stored it in the mud where I found it years later, looking like a solid but rusty bar. Not such a mystery after all then.
That's what I was thinking. Another 1/8" shorter, I'd have called it good and presented it to an expensive cutter - snap, crackle, pop as the end ripped off.
