Published Jan 1. 2001 - 23 years ago
Updated or edited Jan 11. 2017

Hook anatomy

Let's look at a hook, and try to put the right terms on the right parts. This picture shows a hook (note that it actually is a rare vertical eye hook, great for this purpose).

Hook schematics

Let's look at a hook, and try to put the right terms on the right parts. This picture shows a hook (note that it actually is a rare vertical eye hook, great for this purpose).
The letters represent:

  1. Eye width - a good measure to use when indicating small distances in the pattern, especially in the front
  2. Overall length. The hooks 'outer' horizontal dimension
  3. Shank length. The length of the part we normally tie the fly on
  4. Bend - it can be difficult to determine where the shank ends and the bend begins, especially on curved hooks.
  5. Barb length - sometimes use to measure out tag/butt placement on salmon flies
  6. Gap (or sometimes gape) - almost the same as the hooks' overall height

Read more about salmon fly dimensions

I have selected a straight shank, straight eye hook for this example, but hooks can be very different from this scheme as you see here:

Two Partridge Bartleet hooks: heavy and fine. This is a very beautiful, classical hook, and it's my favourite for tying salmon flies.

The Tiemco 80x series is a series of short, thick straight eye salt water hooks. Very durable and practical, but not exactly beautiful. They are a bit on the heavy side, but good for certain purposes like The Gift Fly.
The Partridge John Holden hook is very similar to these, but made of thinner wire.

A grub hook with its extreme bend, is used in the salt as the sedge hook for small imitations. It's a very robust hook with good hooking ability thanks to a good angle between line/eye and point.

A typical sedge hook which is used by many Danish fly tyers for small crustacean imitations - and for sedge larvae of course.

The classic limerick bend is still one of the most beautiful for wet flies. These hooks are not widely available any more, but both Partridge and Mustad has some like this one.

Special hooks for bead heads feature a large hook gap and a smooth round bend. The bead slips over the point and barb with no problems and can rest against the eye of the hook.

Same hook different eyes. This is the same Kamasan dry fly hook. The only difference is the up/down eye. It makes quite a remarkable difference on the overall look of the hook and the look and character of the fly.



I have to depend on ...

I have to depend on mail order when buying hooks. The problem is the length of the body, in variable "long shank" type hooks one never knows what this is when ordering Today we have much more information on the size of the insects than in the past, most given in mms. Example; if I wanted a hook for a stonefly nymph of 20mms body length, or a dry fly in 12mms, what do I order? I know which are heavy and light wires and the gape size, but not the length.
I think it would be helpful, especially for new fly tiers, if we had some additional spec like a #6/20, the 20 being body length in mms, rather than say 4X, which can be confusing.
Then again what is wide gap hook? Surely it is only a larger size gap, or gape, on a shorter size body length 2 or 3X short, which again is not clear as to the actual body length.
Add to this the variables between hook manufacturers, it would seem time to perhaps review this system and bring it up to the present day?

I beg to differ with...

I beg to differ with one of your terms. (F) is not the "gap" but is the "gape". The "gap" is the space between the shank and the tag end of the bent eye. For a better detail see the book by William Schmidt "Hooks for the Fly" published by Stackpole Books.


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