Thread a crimp bead and one end of the spring clasp on to one end of a piece of tigertail.  Thread the tigertail back through the crimp bead then squash the crimp bead. Thread on a selection of beads to the length required, allowing the first few to thread over the doubled over tigertail.  At the half way point, before completing the necklace, thread on a jump ring. Loop the tigertail over the other end of the spring clasp and thread back through some of the beads.  Trim any excess tigertail and squash the crimp bead.  Thread a pendant onto a head pin.  Use pliers to form a loop at the end and slip it onto the central jump ring.  If required, thread beads onto an eye pin and fasten this between the necklace and the pendant to lengthen the drop.