Let’s say you are presented with the choice between two blanks that are equivalent in all ways. I’d like to use the word “identical” but I think some would object.

Blank A has little to no clearly defined spine. Blank B has one of the most pronounced spines you have ever felt.

Which one would you choose? Would you consider either one to be an indication of quality in anyway?

Russ in Hollywood, FL.

Because rod twist is a function of guide position rather than spine, it really doesn't make much difference. However, I'd think that most (but not all) builders would prefer a blank that had no spine whatsoever.

I prefer a blank that has a slight overall bow or curve from butt to tip, so that when guides are added it ends up being straight. This is becoming less important, however, with the advent of lighter and lighter guides.

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Russell,
I agree with Tom.
I don't think the presence or absence of a small or pronunced spine has much to do with the performance of a rod blank.

Choose the blank, based on your needs, whether it is a particular action, blank weight or some other particular characteristics.

If, as Tom pointed out - the blanks were really identical - except for a pronounced spine on one, and virtually none on the other, I am guessing that most folks would pick the blank without the spine, simply because it would be more tolerant for building styles.

Take care
Roger

Couldn't care less about the spine! To me straightness is MUCH more important

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!

If I could get one with NO spine then I would want that one..

I'm with Mike.

jeremy

There are several things that cause or result in a blank having a spine. All of these things are the result of manufacturing process problems or design flaws. Why would anyone want a blank with a flaw if it could be avoided?

As Emory stated, no detectable spine would suggest every aspect of the design / manufacturing process was dead on the money. A perfect blank if you will.

Some of the anomalies that create a spine aren't exactly "flaws," although several are. The thing is, the process by which rod blanks are currently created mean that you're not going to have a perfectly straight tube with verbatim wall thickness all around the circumference. It can't be done with the current process by which rod blanks are made.

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Tom Kirkmna's last post - read carefully

Then think about this -

Those who use the pressure roll with the butt of the rod on a flat smooth surface to determine spine location - find what is considered as a "hard defined spine" may be fooling themselves.

What happens if the butt of the blank in contact with the flat table is out of round?

I am very new to all of this and learning as much as possible but I have found with this, my latest hobby/obsession, the more questions I have answered the more questions I have. So here we go, If a rod wants to come to rest on its "spine" when "tested", then the rod actually is "stiffer" on this side, due to the nature of the manufacturing process. This would mean that the rod would "pull" better to one side than the other by using the spine to your advantage. It would basically "want" to pull the fish towards you. Why would you not want this? It seems like a naturally built in advantage. Kind of like a spring with one side doing slightly more work than the other.

The effective spine is the softest axis, not the stiffest. The stiffest will be along the straightest axis. Few of us, if any, cast or fish a rod on a single axis.

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Still, with that being said, when you spine the rod and place the eyes you are indeed using the stiffer side of the rod to your "advantage." Seems to me if you give up the spine you give up the advantage.

No, if you put the guides on or opposite the spine, the stiffest axis will be somewhere off to one side.

And again, you don't fish the rod on a single axis.

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OK. I understand now. I also understand why the "spineless rod" would be the more desirable of the two. So with this newfound knowledge, at least 2 more questions are born. 1. how do you find the straightest side of a blank and, 2. Given the fact that we do not work off a single axis while actually using the rod, is finding the "straightest" side really that important?

No, it's not that important. It's usually done as a point of reference. The straightest axis when oriented so that the tip and butt are high and the belly of the natural curve is low, tend to flatten once the weight of the guides is added.

You can generally find it by eyeballing the length of the blank. Or, you can support the butt at two points, about a foot apart, and then rotate the rod blank and watch the tip against a grid of some type (graph paper is fine). When the tip reaches it's highest point, that's the straightest axis (and generally the stiffest as well).

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If I makean inventory order with a bunch of blanks same model, and I want to build one for myself, I have always pulled th blank with spines 180 from each other for myself. I don't kno wi fit matters, if th rod is defctiv, or anythign els, I know I'm happier with th blank that is like this, and I've neer had a blan kfail du to this, but they have popped from extreme high sticking & overloading.

Thanks everyone. Jim's post summed up my "belief" to a tee.

Richard, you might be better served forgetting you ever heard the word. I can't think of another rod building topic surrounded with more misinformation. Perhaps you know this but I'll throw it out there as you ponder ways to build for maximum pressure on the fish. The rod fibers on the inside of the curve (towards the fish) are under compression and the ones of the outside are elongated. It is the ones under compression that will fail first.

I'll have to think up something better for my next question.....always been curious what the general feeling is on dual helix constrution.

Russ in Hollywood, FL.

If every single aspect of the blank manufacturing process were performed perfectly - you would still have a spine effect. That type of construction ensures that you'll have such a thing. It actually creates it.

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Well stated Tom.
Now the question.
Since it will always be in the construction is it possible to use it for a practical advantage in some aspect of fishing ?? ie if the rod will fail in compression is it better on the compression or tension side of the blank ??
In your rod breakage experiment did you find any correlation between failure vs spine orientation ??


Eugene Moore