Check with Superior Threads - www.superiorthreads.com or 1-800-499-1777. Their website also has a helpful "Thread Reference Guide for Home Machines" that has five columns of information for each thread it manufactures. Maybe you can find a sewing machine repair person who is not locked into a specific brand machine. All this aside - it sounds to me like you are threading your machine through the tension disks with the presser foot down. None of my machines cooperate when the foot is down. Check your manual. Some actually warn you against this practice. For instance, the first sentence under "threading the upper thread" for my Viking Sapphire 150 says to make sure the presser foot is raised and the needle is in the up position.