Keeping on the Bobbin theme this week.
So, what do you do while you are filling those 3 or 4 bobbins? And why do you not fill 5 or 6 bobbins? Because you need to clean and oil your machine every 3 or 4 bobbins. While the machine is winding, open it up, take out the bobbin race, brush everything out really well, oil as indicated, and wipe down the machine. Should take you about 3 or 4 bobbins worth to get that done.