Below is a picture of the bobbin winder array. I put the end of the thread through a hole in the plastic bobbin, wind several turns excess in a clockwise direction, insert the bobbin on the spindle and then slide the thread through one of the grey appendages on the winding spool. The grey lever engages manually and stops automatically. Once the spool is full, there's another cutter to the left of the bobbin for easy removal. Fairly consistent results with this method so far. I like the separate motor, which means no more disengaging the flywheel clutch. Perhaps using the second spindle will also avoid having to rethread the needle. Buy two spools and never be lacking. The size is a Class 15 standard plastic.