check Callaham site
there s a good explanation of why trem arm brakes.
Their trem assembly rock
1st thought, lay off the caffiene.....
Try a little thread tape around the thread. This is the same stuff that is is used on threaded brass fittings etc. It stops it rocking so much in the block thread mount and may help a little. I like my arm unwound one turn so it dangles down and this worked pretty well for me though the thread tape stops it being totally loose.
If you broke two of them, you're doing something wrong. Strat whammies aren't made for extreme dive bombing. :Spank
I agree, these things really weren't meant for dive-bombing, think of the era that Leo designed them in. I can't imagine breaking two of them!