As a fly tyer, we always hear that the smallest possible thread is the best to tie our flies with. Although a small-format thread generally gives better results, there are exceptions.
Tying thread comes in different sizes, usually calculated in deniers. It is a unit that measures the size of the thread by the weight for a length of nine meters. One denier equals one gram for nine metres of thread. Following this, a 70D size thread is two times smaller than a 140D size thread.
A smaller thread, what is it good for? A thread of smaller diameter will help us to do a smoother and smaller underbody and won't add any unnecessary bulk on smaller flies while also helping to tie smaller heads. Small-headed flies, which we should discuss in the future, is a very simple way to spot an advanced tyer versus a beginner. So, is a small thread always the better? It depends!
When tying specific materials, such as peacock herls and eyes or even deer body, a thread that is too small focuses all the pressure on a really small area, which will likely cut the material instead of securing it.
If we use, let's say, Semperfli Nano Silk on a bomber type of fly, if too much pressure is applied on the thread (which is easy, as it is a really strong thread), we will cut the deer hair instead of simply flaring and turning it.
On the other hand, a thread that is too big won’t be suitable for all situations either. The UNI Big Fly for example is perfect to add bulk in front of a reverse deer hair, but if you try to attach a gray squirrel wing with it, the pressure will be scattered on a large touching surface, which results in not enough force to hold the material right in place and will let it slip through it.
In a way, tying threads are much like golf clubs. You can try to tie every fly with one single type of thread, but the truth is that you will likely hate your experience, just like if you were to play a full round of golf with a putter. You should select the right thread for the right fly. If you are a beginner, a couple of colours in 70D and a couple of colours in 140D should go a long way!
and then Add to Home Screen.
