If it was a problem with the spool I don't think it would break a needle before the thread. Are you using a spool that has a slit in the edge of the spool, that will catch every time binding up everything. Put a full bobbin of thread on the spindle and see if that will sew without breaking. That will test if it's the spool. The needle may be hitting the feed dogs that may be out of place just a smidgen. Try raising the feed dogs up and down a few times.