Thank you for your question. It could be many different issues, one would be the needle needs to be changed. As needles wear, they actually can get sharp where the needle is constantly coming in contact with the eye of the needle and that may cause shredding. Another could be that the thread is old and dried out. I also have found that occasionally with lesser quality thread, shredding occurs more often. Also the type of thread can differ. For example, when using Rayon thread I need to slow down to prevent shredding. Another issue may be that you have a burr somewhere in the mechanism of your machine, (highly unlikely). Always try to rethread your machine and change the needle. I have also heard that a product called, Sewers Aid, which is placed by the drop onto thread will condition the thread and help it not to shred. I hope this is helpful and I apologize for taking so long to answer. Good luck and let me know if any of these suggestions help. :)
