Yes - oopses happen to all of us. I was making this rather handsome necklace, and I secured the final crimp, added the crimp cover, trimmed the line, and all seemed well. I went to try it on, and the crimp let go on one side. It had gone on sort of crooked - but resisted my tugging - so I thought it was okay. The clasp slid off - leaving me with a short, short end that there was no way I going to get back through the clasp and into a replacement crimp. OK - how to fix this without restringing the entire piece?

Fortunately, there

were some beads in the pattern that have really big holes, and one not too far away from the clasp (about 2 inches) - perfect!
I unstrung back to the big-hole bead, and removed it as well.

I then took a new length of bead wire and slid a crimp over it and the new wire, and slid it the crimp right up to the last strung bead on the necklace. I left a tail on the new piece of wire.

I then crimped that into position. And to be extra sure of the connection, I tied the tail of the new wire over the crimp to the tail of the old wire.

Then I put the big holed bead back on - sliding it over the crimp with the knot over it (it needed a little encouragement) and I had 3 wires sticking out - one long one and and two short ends. I trimmed the two shorts ends, and then restrung the rest of the necklace, reattaching the clasp at the end - more carefully this time.

Voila - all better now and who could tell!
My copper turquoise necklace with dragon and phoenix beads has risen from the ashes of disaster!
The upside of failures like this is that I get a blog post out of it.
I live to be a bad example to you all!
I'll post this as an inspiration shortly if you want to make your own!