I recommend using "Append" method for bringing elements to the scene. This method works better for elements in groups.

For Append elements in Blender: 

File ••••• Link •••• Open file  UI_elements_with_splines.blend ••••• Group ••••• pick your element type from 1-30

Before adding screws to the scene, look for the file  UI_elements_number_map.jpg  for the exact element number.