Repairing a Kenmore Bobbin Threader Clutch?

It sounds like the thread has been stripped on the wheel because people tightened this so much. If you can't remove the side plate the screw is rusted and in there so tight. I would try a little bit of WD-40 on the top of the screw to see if you can get some of the rust off of the screw so you can loosen the screw and take it off. You will need to order some new parts for this machine in order to get it working correctly again. You will more than likely need a new clutch wheel and threader to start off with. On top of this if you can't get the screw removed a lot of times it has to be drilled out and this can be a very difficult job to do so you don't damage the hole and the threads when putting in a new one.

If you don't have all the proper tools to work on this I would like to suggest that you take this to a sewing machine shop and ask for help. I would hate to see you destroy the screw on the plate because you can't get it off. Do not force the screw off because you can also damage the head of the screw which will make it even harder to remove.