In a conventional dubbing loop the thread is doubled around the arm or arms of the dubbing loop tool (depending on the type of tool chosen), and a thread turn applied around the very top of the loop adjacent to the hook shank for improved grasp of the materials to be introduced into the loop before spinning.
For medium to small flies split-thread dubbing is an approach Wayne often prefers because he finds it is quicker and, more importantly, it reduces bulk by using a single strand of thread instead of two. With split thread dubbing the “loop” is created by splitting untwisted, linear fibered thread with a bodkin, placing the dubbing between the strands of split thread, and twisting.
READ WAYNE'S ARTICLE