Crimping is simply squeezing or flattening specially designed beads and tubes to secure jewelry elements (like clasps or beads). Usually, you use crimping to finish a jewelry piece in a clean, professional manner. A quick and easy way to finish jewelry is to use a pair of crimping pliers and the two-phase crimp method:
Position your strung crimp tube or bead in the lower jaw of the crimping pliers. Squeeze the jaws together to reveal a bent crimp that resembles the lefthand image.
Move the bent crimp up to the top jaw. Squeeze the jaws together to further flatten the crimp, leaving a professional look, like the one in the righthand image.