The information says the auto stop is based on number of revolutions, and how many it takes to fill the bobbin will be dependent on the thread weight plus bobbin size - so if you use a 60wt and set your stop setting, and then use that setting for a 40 wt thread, one would expect you'll have problems.
I'd buy this in a heartbeat if it weren't for that. I need about 6 settings since I would use it for two machines with three common thread weights.
Last edited by Macybaby; 03-20-2019 at 07:03 AM.