For a fastener to do its job, it must be tight.
As a fastener is tightened it is forced to stretch.
Fasteners work like springs. When you stretch a spring, it pulls back – trying to return to its original size. The stretching force is called tension. The force that pulls back is called compression.
The stretching force on a fastener is also called tension. The tension creates clamp force, which holds things together.
Tap the images above to see how compression, tension and clamp force work.