XL-3500/ 3510/3520 FAQs & Troubleshooting XL-3500/ 3510/3520 Not your product? Patterns How-to information about sewing patterns. Presser foot How-to information about presser feet. Needle/Thread/Fabric How-to information about needle, thread and fabric. Tips for sewing Useful information about sewing. FAQs & Troubleshooting