Schacht Bulky Bobbin for faster whorls in double drive

This bobbin is for those with Schacht wheels that can utilise double drive, and for those spinners who want to use the bulky flyer to spin and ply large amounts of finer yarn using the fast and high speed whorls. The ends are interchangeable, as they screw onto the core. The fast bobbin end will work with the fast whorl, the hi-speed end will work with the high speed whorl, and the silly speed end should enable double drive plying with the high speed whorl. I've also added a plain end, which