I’d like to make a pearl necklace — I bought some clasps for it, but I’ve run into a few problems. One of them is that when I press down the crimp tube, it eventually cuts through the thread or wire. I guess the pressure causes it to rub and break. So far I’ve tried using wire and special beading silk thread, but they only lasted a few days. I can’t use anything thicker because the pearls have a small hole. Another issue is that over time, both the wire and the thread stretch out, and eventually a gap of about a centimeter appears in the necklace, which looks really bad. "What would you recommend? What kind of thread or wire should I use for stringing, and what type of clasp do you use?