Q. Just tried the class 15 So Fine! #60 bobbins with So Fine! #50, So Fine! #40, So Fine! #30 and Fantastico on top - on my friend’s Janome Horizon. Superb results! And didn’t even have to make any tension adjustments. Just wondering, why So Fine! #60 instead of Bottom Line on the new bobbins? (love the look though)
A. Our So Fine! series of threads are not as slick as Bottom Line. Although they are both filament polyester, So Fine! has texture added into the thread to give it a bit more grab. As a result of this texture, it is not as slick as Bottom Line. Plastic-sided bobbins and a slick thread can be a problem for some machines, as the slick thread wants to keep unwinding after the bobbin stops spinning. This is known as 'backlash'. For this reason, we decided to use So Fine! #60 as our light-weight thread to wind onto Class 15 prewound bobbins.