Originally Posted by Dave Mayer

I spent much of the 80's punishing my bike and body riding over roots and rocks. In those days, all 'mountain bikes' had 1" threaded headsets. I faced the constant problem with headset loosening, until I finally leaned how to correctly tighten up headset threaded bits. First, you need to properly pre-load the bearings. Then, using two (big) dedicated headset wrenches, tighten the top nut and threaded top cap against each other. Note the emphasis, you need to scissor these two parts against each other - tight, without messing with the preload of the headset bearings. Simply tightening the top nut will lead to the headset loosening again, within one ride. Once I learned this, never had a problem again.

BTW: I do not see any problems with your headset parts. If your crown race is brinelled, then I suggest you re-install it rotated by a few degrees, throw away the ball retainer, and replace your current ball complement with a greater number of loose balls of the same size. That way, the higher number of loose balls cannot line up with the pits caused by (false) brinelling. I've done this operation many times; the headset will feel new again.