Вот описание этих понятий:

Bottoming, which is engagement of the threads of the stud with the imperfect threads
at the bottom of a shallow drilled and tapped hole, causes the stud to stop suddenly during
power driving, thus inviting failure in torsional shear.

Shouldering, which is the practice of driving the stud until the thread runout engages with the top threads of the hole, may create excessive radial compressive stresses and upward bulging of the material at the top of the hole.

Меня интересуют только два этих термина!

Bottoming - перекос, заклинивание?
Shouldering - деформация при избыточном усилии затяжки?