I ran into this issue when I first received my e-spinner (an EEW Nano 2 in this case--not the wheel's fault.)
To fix a leader yarn that is sliding around on your bobbin, use a grippy yarn such as acrylic to start. You'll want to attach it securely to the bobbin; it will still slide at this point. The trick is to loop the yarn onto the bobbin (in a loop cast on style) several times so the yarn is hard to impossible to move around the shaft of the bobbin. This will drastically aid in the uptake of the spun fiber for spinning.
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