Since you put this machine together from parts you have to make sure you aren't mixing 221 parts and 301 parts.
If any of your parts are from a 301 they all have to be from a 301. Mainly the rotating hook assembly and the
needle plate have to match from the same type of machine. You can tell from the part numbers stamped on the
parts. If you use a 301 plate with a 221 hook etc you will have all kinds of problems. They look the same between
221 and 301 but aren't. A lot of people out there are selling 301 parts saying they are 221 parts.