I cannot figure out what is wrong with this machine. It's sewn one holster and I've played around on scraps a bit. The (locking knot?) keeps showing every other stitch. Sometimes on bottom sometimes on top. Here's a pic of what I mean. I've taken the bobbin out and respooled it. Making sure it's laying flat and the thread doesn't stick out the side hole. Installed it making sure it's turning counter clockwise. Cut the thread off at the spool and re threaded making sure I went through each k