Not all metallic threads work in every machine. Some shred easier than others. A metallic needle helps. I also find that sometimes I have to reduce the top thread tension to almost nothing to put less stress on the more fragile metallics. And then that doesn't always work. I love metallics and so have found ways around most problems. The last metallic I used, I could only get to work if I used the same metallic thread in the bobbin and left the tension alone. Good luck!
Marian :-)