By Gordon van der Spuy, photos by Leonard Flemming

In the last issue I spoke about hooks. This time I want to tackle thread. Thread is possibly the most neglected aspect in tying today. Most tiers don’t give it the attention it deserves, probably because they don’t understand thread and its application properly. “What’s there to understand?” you might ask, “…It’s just thread?”, and that’s the problem, it’s not just thread!

I have taught over 350 fly fishermen the finer aspects of fly tying in the last 5 years and not one of them understood thread fully. The majority of them rocked up to my workshop with Danvilles 140 Denier, this is the thread which they viewed as being a good general thread. Most of the tiers I teach are guys who have been tying flies for a few years but who feel their tying has reached a ceiling. With 140 Denier as a general thread of choice fly tying will hit a ceiling! Once these guys grasped thread properly their tying blossomed. I think of people like JP Gouws who but a few months ago was struggling to tie an Elk Hair caddis. The guy is unstoppable currently, his wife probably rues the day he came to my tying lesson.

Form follows function – the thread you use will be dictated by what you need it to do whilst tying with it. Your thread is what keeps everything together when you’re tying and when you’re actually fishing the fly but also has a major impact on the final product that rolls off your vice. Thread choice can make or break a fly.

Thread choice and thread control are very important things to consider when tying. Very view tiers I know are aware of thread control. They think thread control is all about thread tension and to a certain degree it is, but there is a lot more to it than just that. Most guys just wrap thread without giving too much thought about what they are actually supposed to be doing with it whilst tying.

Thread control is exactly that, control. To understand thread control however, the tier needs to understand the mechanics of thread when wrapping it. First off though, I like using flat threads that consist of many individual fibres and I like using the thinnest thread I can get away with. Not all threads are flat; some are braided or twisted. I avoid those products. I prefer flat threads because they are more versatile, I can use them flat or can twist them up if the mood takes me there.

Demonstration of how to tie with a flat thread
Demonstration of how to tie with a flat thread

Flat threads twist up when you wrap them, to illustrate the point I’ve used a flat piece of tinsel. With every wrap the twisting of the thread gets more pronounced. When you let the bobbin holder hang still below the hook you’ll literally see the thread untwisting. This will generally be in an anti-clockwise direction when viewed from the top, but not always. You need to look at where the thread comes off the hook shank to see when it is flat. You can help the untwisting process of the thread by spinning the bobbin in the relevant direction with your fingers. Do this every few thread wraps and you’ll find yourself improving thread control drastically. What thread twist does is lead to thread build up, you simply use more thread. By untwisting the thread as you tie with it you actually use less thread as the thread is spread out over a larger surface area thus keeping bulk to a minimum.

Untwist the thread by spinning the bobbin in your fingers
Untwist the thread by spinning the bobbin in your fingers

Small details like this are what set really good tiers aside from the millions of average tiers out there. Good thread control simply gives you more options. If you’re sceptical try tying a #22 parachute Adams. You can’t do it if you don’t have thin thread and good thread control. This is what I mean by options.

Modern fly tying threads are far more user friendly than the threads of old, but these days a wide range of threads are available, which confuses especially the newcomer. That said I predominantly use four different threads for all my tying. I don’t believe in buying ‘one hundred’ spools of thread. I don’t think you need them although there will probably be people out there who strongly disagree with me.

I’m a fan of white threads, it’s easier to see what the thread is doing whilst you’re untwisting it and lighter threads also offer a lighter ‘underbody’ allowing the materials used in the fly to retain their natural colour when wet. Dark threads will cause the material to go darker. This is not necessarily a problem. White threads just make tying easier for me. I can see what I’m doing and I like that. It gives me ‘control’. If you’re worried about a white thread head all you need to do is touch the thread with a marker of your choice before applying varnish.

Tie flies with a light coloured or white thread that is untwisted and unwaxed
Tie flies with a light coloured or white thread that is untwisted and unwaxed
Colour white thread with a marker pen before applying varnish
Colour white thread with a marker pen before applying varnish

Threads come in varying sizes or densities, in Victorian times thread sizes were denoted by a system of zeros, the more zeros the thinner the thread. A 14/0 thread was thus thinner than say an 8/0 for example. An 8/0 was thinner than a 6/0 and so on and so forth.

The Americans then came and used their own system which they called Denier, this system works exactly the opposite way to the old Victorian system (go figure!?), a 70 Denier thread is say thinner than a 140 denier thread. A 140 denier is thinner than say a 210 denier and so on and so forth.

Many tiers get confused by the numbers. You needn’t, simply look at the thread and ask yourself these questions: “Is this stuff thin or thick enough for what I need it to do?”; “Is it flat and will it perform the function I need it to perform?” Twisted or braided threads can’t be split for example, so if you were tying a little split thread cdc pattern the thread would literally inhibit you from tying the fly. Use the right thread for the job at hand. Trust me, it makes a big difference. Get this right and you’ll take your tying to the next level.

1 - Split Gordon Griffith's Sheer with the tip of a hook or needle
1 – Split Gordon Griffith’s Sheer with the tip of a hook or needle
2 - Insert CDC fibres into the split thread
2 – Insert CDC fibres into the split thread
3 - Pinch the CDC fibres in the thread and spin the thread to form a CDC brush
3 – Pinch the CDC fibres in the thread and spin the thread to form a CDC brush
4 - Wrap the CDC brush to form a thorax, for instance
4 – Wrap the CDC brush to form a thorax, for instance
5 - The completed, sparsely wrapped CDC Klinkhamer
5 – The completed, sparsely wrapped CDC Klinkhamer


  • Use the thinnest thread possible for the job at hand;
  • Ensure that you work with a multi stranded thread that is flat and not twisted or braided in any way. If you want the thread twisted you can always twist it up by spinning the bobbin holder;
  • Avoid waxed threads if you want to work with flat thread. Wax clumps thread fibres making the untwisting procedure difficult, also waxed threads gather dust. If you need to wax you can always add it later. Unwaxed threads are more versatile as they give you more options;
  • Tie with light or white thread, it is easier to see what you are doing and the fly’s proportion can be worked out with a marker;
The proportion of the fly can be marked on lighter threads
The proportion of the fly can be marked on lighter threads
  • Always use a ceramic bobbin holder, the old school tiemco bobbin holders are awesome and won’t fray your thread;
  • These are threads I would recommend:


  • Danvilles flat Unwaxed 6/0 – a great all round thread for average sized flies, #2-#14;


  • Griffiths sheer 14/0 – My go to thread, I use this stuff 90% of the time, awesome stuff; it is good for split-thread work too. Will tie down to #22 no problem;


  • Uni thread trico 17/0– A specialist thread for the guys who realise that dynamite does sometimes come in small packages. Good for the really tiny stuff. I’m talking 320s and smaller;


  • Danvilles 140 denier flat unwaxed – This I use for spinning deerhair and larger flies like woolly buggers and zonkers etc.


These threads are by no means the be all and end all in terms of tying threads. This is what I personally like. If other threads work for you go for it. It’s about function, if other threads function better for you use them!

Trout close up small

Leonard Flemming

Leonard Flemming

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One Response

  1. Lekker. And for the tiers who are into the bigger stuff more often (e.g. bass, largies, tigers, saltwater, etc.), Danville’s Flat Waxed Nylon in 210 Denier is a must-have, it’s moerse strong and very useful for all sorts of things. I’ve yet to find it in an unwaxed version, but the wax coating is so light as not to be a hindrance at the scale of the ties it’s used for. The next step beyond that is Kevlar, which has some applications too.

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