[dtw]

Nut onto a stud: load is place onto the threads on the exposed end of the stud. Ideally there is no torsional force on the threads already installed into the case.

Bolt into a case: all load is placed on the magnesium threads. Very Bad Thing.

Think of the heads studs. There is no load applied to the head studs when they are installed into the case, nor are they even threaded all the way in. They are frozen in place with red loctite. When the heads are bolted down, the torsional force is on the stud, not the case. There is force applied to the case parallel with the stud, but not torsionally. It's the torsional force that strips the threads in most cases. I hope some of this makes sense.