Stonfo Bobbin Threader. Fly Tying threader. Fly tying tools for sale. Threaders Fly tying tools for sale. The single wire model is useful for bobbins with narrow tubes while the loop model makes quick work of a common task. Stonfo Wire Bobbin Threaders for fly tying - The loop wire is perfect for standard or larger size bobbins and the single wire is ideal for narrow tubed bobbins Online shopping equipment, tools and materials Shop from the world's largest selection. Buy fly tying tools.