Double-Bobbin for Ashford Joy Spinning Wheel

As I always wanted a bobbin with two seperate chambers for spinning and plying afterwards, I designed this double-bobbin for my Ashford Joy spinning wheel.
With this bobbin, both halfs of the bobbin can be filled with singles.
And afterwards they can be plied together and the yarn will fill a complete bobbin.
The designed bobbin has a coupling part, so on the spinning wheel both halfs turn together. And on a lazy cate the coupling can be removed and both halfs turn alone, so that they can b