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AFTM [Versión en español]

When casting, the rod acts as a flexible lever. For the purposes of 'thinking' about casting it helps to think about flexing the rod. This is what gives 'feel'. The caster flexes the rod by moving the rod tip against the flyline mass.

You will probably have noticed that the rod has a whole bunch of writing just above the handle. I certainly hope so, otherwise are you going to have some fun! Somewhere in amongst that text you should find the AFTM number. AFTM #4 would be an example. Sometimes the rod has a range of numbers AFTM #7-9 say.

AFTM stands for the Association of Fishing Tackle Manufacturers. AFTMA stands for the American Fishing Tackle Manufacturers Association. Just in case you were wondering.

The AFTM is a scale of line weights. The heavier the line, the greater the AFTM number. The manufacturers weigh the first 10 yards excluding the level tip and rate the line according to the table.

AFTM Table

AFTM number In grains (range) In grams In ounces
3 100 +/- 6 6.48 0.228
4 120 +/- 6 7.78 0.274
5 140 +/- 6 9.07 0.32
6 160 +/- 8 10.42 0.366
7 185 +/- 8 11.99 0.422
8 210 +/- 8 13.61 0.48
9 240 +/- 10 15.55 0.55
10 280 +/- 10 18.14 0.64
11 330 +/- 12 21.38 0.75
12 380 +/- 12 24.62 0.86

Incidentally, there is some controversy with regards to very end of the flyline. The level tip on some lines can be as much as 2 ft. This, I believe, was an industry standard. I have also heard that it was also a manufacturing fault and the level tip should in fact only be 6 inches.

The point of all this is that the flyline AFTM should match the rod's AFTM.

If you were to put an 8 weight line on a 4 weight rod you would probably break the rod. You would certainly overload the rod and make it feel slow and sluggish.

If you were to put a 4 weight line on an eight weight rod you probably would find that the rod failed to bend very much and the casting would be crap.

However life is more interesting:

The first point is that all quality rods have a progressive action. This means that the greater the mass used to bend the rod, the more the rod flexes. Therefore you can force a greater flex into the rod by either casting with a heavier line, or by aerialising more line outside the rod tip. Up until now we have been casting with 10 yrds of flyline. Aerialising an extra 1 ½ yrds of AFTM6 is the equivalent of 10 yrds of AFTM7.

This alone is not very interesting until I tell you that the greater the flex in the rod, the further the cast. Of course you can still overdo things and overload the rod. If you stick too much weight outside the tip ring, at best you will make the rod sluggish ('soggy' for the technicians out there), at worst you will destroy your rod (either it will break just above the handle, beneath the handle, or at some other place altogether!)

We can get thoroughly involved in the AFTM system and disappear in to some dark black hole and at some point I certainly would like to do this. Believe it or not, it can get very interesting, especially when you realise that by dropping the AFTM number and aerialising more line you can bend the rod just as fully as otherwise, but you now have a thinner and therefore more aerodynamic flyline.

I've been paid in the past to assess rods and give them an AFTM number, and I can tell you that multiple ratings are bollox. ALL rods can be used to cast a variety of line weights, this is so that you can cast 5 ft and 105 ft. What the AFTM of a rod should tell you is what the assessor thinks is the best line fit for that rod and its intended purpose. This is one of the things you spend your money on when you buy a rod. Quality rods are correctly rated. Many rods, especially those originating from outside the US, are very ambitious in their line ratings.

Now that you have an understanding of the AFTM scale I'd like to briefly touch on some other properties of flylines…

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