I have 5 (?) machines that use the long bobbins. Only one of them winds evenly from end to end. The others will wind a lot at one end but not at the other. One will wind a lot at both ends but not the middle.
I'm using bobbins that fit as best I can considering the age of these machines.
Some of the winders show a lot of looseness and wear which contributes to the inconsistent winding. Others are just off somehow.
I've tweaked a couple of them, improving their winding, but not getting them 'right'. Even though some of them were gummed up badly I did not take them apart when I cleaned them. So it's not that I assembled them wrong.
Does anyone here have any words of wisdom they'd share on how to fix and adjust the long bobbin winders?