Thank you everyone for your kind and helpful words. I changed the thread as it was the X style to horizontal. It sews for a while but then the material stops moving forward. I do have a manual and I have nearly worn out the troubleshooting page! It says a cause for my trouble could be that the pressure foot is too light, but I can find how to adjust it. It was sewing fine when I made some face masks. I've checked all around by the bobbin and don't see any rogue threads. The thread on top looks good, until it stops moving forward, but underneath it is loopy and jumbled. Man! I'm just trying to put a patch on my favorite sheets! Thanks again! Sorry for the trouble!