Week 6 - Twisted or Flat Thread
Your tying thread is the proverbial glue that holds your flies together. Being such a simple thing you would not think that fly tying thread could be a complicated issue but there are many facets to thread that effect the durability and quality of your fly. One such property is whether the thread comes off the spool twisted or flat. A twisted thread is stronger but a flat thread is smoother so, which should you use?
First, understand that a thread is twisted (clockwise) on the spool to simply help the thread from drifting apart while you are using it. Any twisted thread that you use can be flattened by spinning the bobbin counter clockwise. Also, be aware that as you wrap your thread around the hook you are putting in a 1/2 clockwise twist for every revolution around the hook. So if you are already using a twisted thread you are twisting it tighter as you wrap thread on.
There really is no one solution because for different flies or at various stages of tying a fly it might be better to have a twist and at other to have the thread flat. I prefer a thread to come off flat so if I need a twist I can put it in. This way I can untwist is when needed, like when putting in the whip finish. The thread in this last image is UTC thread and it has a very slight twist in it (take a look at the fist image) but for the most part comes off flat. I can use it to have a nice flat base or even for the bodies of small flies but if I need something stronger or something with more of a segmented look I can easily twist it up. As you can see the thread is very different whether it is flat or twisted when it is wrapped on the hook. The end decision it both have their place in your flies.