I put a size 15 (very thin) beading needle horizontally in a vise.
Then I use that as mandrel to tie most of they fly.
The body is a duck flank feather, over-wound with thread.
Add some tail fibers. Wind back to the front. Tie on some wings (which could be Zelon).
Knot it off. Pull it off the needle. Put a scud hook in the vise.
Tie on a hackle feather. Mount the body on top the hook with 4 loose wraps fore
and aft of the wing. Wind thread horizontally 6 times or so, which forms a thread post
between shank and body. Wind the hackle. Tie off with one half hitch.
The fly is now tied, but not durable enough to use. Add a drop of water-based
fabric cement at the fulcrum of the hackle. When the cement is cured it's ready
to fish.
I don't claim these flies attract more strikes. But they do attract strikes as well as any other mayfly.
And they're fun to tie and fun to look at. And they do float well. They're good on-the-water performers.
http://montana-riverboats.com/Robopages/index.php?page=Needle-Butt/AModel.jpg