A Disaster. Within a short time the 3 coils were empty (that was the set of 3). Glad I picked an empty spool. With a little skill and hobbyists 2 small screwdrivers I removed the white plastic retaining ring in the middle and have even drafted a thread. Bought at Amazon, 24 m. 8 m cut and folded in half. In the black spool is in the central bar, a deep slit, here hang the new thread and in direction of the arrow (on the outside of the black spool visible) wrapping up on a scrap piece of 15cm. Pinch the thread in the small notches on the spool, is a bit difficult, and then the white tire raise again. Worked great. The operating time is now longer than the 3 coils together. Repeated filling Although the retaining hoop will eventually break, but until then I can work happily with dynamically loaded coils. Good luck, who wants to imitate it.
