Butchered a $5 hand mixer & now have an ultra-fast bobbin winder ;)
I figured I should give more detail on this, because it seems my website is getting hits for people searching, "how to make a bobbin winder". Lol, who knew? I bought a cheap hand mixer and had a friend cut the end of the beater off and sand it smooth. The shaft of the mixer is just a hair too small to get a good grip on the bobbin, so I built up the thickness of the shaft with clear tape. I just rolled it on until the thickness was right.
Obviously, there's no tensioner in this set up. So I either wind with the thread going through the threading and needle of the machine, (with slightly raising presser foot with the knee lift to lighten the tension slightly.) or, I create tension by pulling thread through my fingers before it goes around the bobbin. That has to be done on the slowest setting, so as not to burn my fingers. ;) The slowest setting is still very very fast but my fingers are calloused from working more than full time every week at sewing, so it's not a problem for me as long as I pay attention to what I'm doing! Ha!