What would cause the block threads to pull out/loose of the block?

What I can think of:
Over torquing.
Repeated removal of bolts/head.

Anything else?

 

btt

 

Some common reasons;

Binding of the threads, causeing some to shear, and then the rest die, caused by not properly lubricating, or getting dirt in threads.

Cross threading in past, weakening thread.

Fatigue causeing threads to break.

Wear, causing reduction in strength.

Paul

 

Thanks, basically all the possible causes seem to be as the result of poor workmanship...