Using the cross peen side of a riveting hammer, lightly tap the end of the wire to begin spreading the metal just like forming a wire rivet.
Continue tapping gently, rotating the clamp as you go to spread the wire evenly.
Switch to the round flat end of the hammer to form a rounded head shape.
As the end flattens against the drilled hole, pull out a bit more wire and repeat.
I pulled more wire out three times in total during the process.
Important:
If you hit the wire too hard or leave too much sticking out, it will bend instead of spreading.
Make sure the wedge end of the clamp is tightly pressed in to keep the wire from slipping back as you hammer.
This method works well for creating a small, flat end perfect for securing small beads and crystals.