Very Very Simple columb uncollapsed (with all modifiers for educational case)I release this model for you to study , i didnt collapsed modifiers to see how i model these bolts.
I used :Editable polyTurboSmoothSymmetryUnwrap uvw
*** This model must not be used in commercial projects (before that must check with me) .
3dsMax 2018 (Corona with material), You can import easily to other formats.