stuck a new blank I ordered in the spine finder It seems to have two spines 180 degrees apart has anyone ever experienced this before?the rod is a two piece 10 ft spinning rod blank the tip section has a natural curve following one of the spines I marked so Im pretty safe in guessing which spine to use for it but the butt section has no noticable curve so Ill probably just pic one and go for it.think this is the way to go?

steve

I wouldn'y worry much one way or the other. IMO,spine doesn't have any noticeable effect on a rod, but that's just my opinion!

Wait till you get hold of one that three detectable spines...lol

If spine worries you, then one of the two your blank has is probably dominant. Wrap according to that. If this is a spinning rod or casting rod that you're going to wrap spiral fashion, wrap on the straightest axis and forget the blank had a spine at all. Best of luck.

Jay

The spine is defined by opposites. Strong side and weak side. One spine, two sides. You aren't finding two strong spines with two opposite weak sides are you??

Just because I have the time............

Spine in most cases doesn't mean much for most types of rods. But let's look at an extreme example where it's effect should be considered. A very long, light weight fly rod, a 10 foot 5wt, for delicate casting of dry flys. If the blank has a pronounced spine, and you mounted the guides on the side, it probably will have something to do with throwing each cast a bit to the side. This can be quite easily adjusted by the caster. Just aim a foot or two left or right of target. Any experienced caster will automatically do this with every rod he picks up. The subtleties of every cast is adjusted to each rod. Fly casting is very much like a golf swing. Timing is far far more important than muscle. Long casts just like long drives come from perfect timing of weight transfer. Good accuracy does not come until the timing is refined, skillful, repeatable..

But as far as spine, for the vast majority of rod types, the effect is so subtle as to be a very minor issue. So far I have only built on US made brand name blanks, and I have yet to find what I consider to be a pronounced spine. It's always there, but very sleight. I do consider it for guide orientation only because it only takes a few minutes to do so. I spend much more time in getting as near a perfect line up of the guides and don't worry much about whether they end up off spine by a few degrees.

I will say that on conventionally wrapped casting rods, I put the guides on the strong side, so when fighting a fish, the rod gives to the weak spine, thereby reducing just a bit the tendance of torque to turn the rod.

Double post, sorry.



Edited 1 time(s). Last edit at 02/11/2006 07:20AM by Tim Stephens.

I have been finding the spine by adding weight to the butt on a blank section. Just enough to make it bend well. Grib the tip with one hand and the blank rests on the other about a foot away. Turn the blank till it seems to find it own flex point. Mark the top. I figure it will be fished this way . Easyer for me to do IMHO Careful of light tips.

Tim,

The strongest and softest axis of most blanks are almost never opposite each other. That would probably occur in less than 10% all blanks built. Nor does spine orientation have anything to do with casting accuracy. This is the sort of thing that really needs to die out - it has no basis in fact and only serves to confuse and worry many new builder. Not trying to give you a hard time, but spine orientation just doesn't have that sort of effect. Never has, never will. It is a shame this sort of thing got started way back when and has managed to survive long enough to worry so many builders.

A badly warped or curved blank, however, can indeed throw the cast off if the curve is not in the casting plane. In this case, I'd work with that natural curve and most likely put my guides on the convex side of the curve for a spinning or fly rod.


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Edited 1 time(s). Last edit at 02/11/2006 10:32AM by Tom Kirkman.

Weather needed or not I mark them. Unless badly curved

Steve,
What you have found with your blank is normal. The two stiffest planes will normally be about 180 degrees from each other and the two softest planes will normally be about 180 degrees from each other. There will also normally be about 90 degrees between the stiffest and softest planes. You may find variations to this because there are half a dozen factors, manufacturing anomalies, that contribute to the spine With most blanks the difference in stiffness between the two planes that are 180 degrees apart, either the stiff one or the soft one, actually will be small. The difference may feel large but if you accurately measure the difference in stiffness it turns out to be small on most blanks.
I agree with the others that you should not worry about it too much. Put the guides where it makes the most sense to you relative to the spine because it is not going to have much effect on the rods performance. There is much to much made of spine and its effect on rods.

Yes, Tom, as I said, the effect of spine is of very little consequence, but if stronger than most, and set to the side, the tip of a long rod will not follow the center of the blank, and the effect can be seen in both the back and fore cast. The effect is not much even with a strong spine bias. For all practical purposes it makes no sense to spend much time at all worrying about it because the effect, if present, is sleight at most and automatically compesated for just by a few casts to get a feel for the rod. Everything else about a custom rod is more important than the spine issue.

That sort of twist is not really caused by rod spine, but by guide location. In one location or the other, the rod will tend to twist either on the back cast or the foreward cast. But as you mention, it is slight. And, when a blank twists around a central axis, the plane of the cast remains unaffected.

Casting machine tests I did over the years showed no affect on accuracy due to spine orientation. And this was all done without the inaccuracies prevelant when you have a human doing the casting.


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When one of my customers is getting his money out to pay for a rod and he asks me "did you check the spine on this rod" my answer is always "Yes Sir I Did"!

Gon Fishn

Hello,
Newbie here from WV and I have finished one spinning rod and working on a casting rod. I have wrestled with thsi spine issue myself. What I found out on my own, and which has been mentioned in an earlier post, is that there seems to be two soft "sides" 180 apart and two stiff "sides" 180 apart. If everyone agrees spining a rod is no big deal I can live with that, but if I want to build a jig rod with the power toward the fish and the hookset, is there an advantage to using the soft side over the stiff side? In other words, should I place the guides along one of the stiff sides? Thanks.

The difference between the softest and stiffest axis is actually quite small - on the CCS ERN scale it's usually not more than about .2 or so.

If you want more power for setting the hook or fighting fish, get a more powerful blank. Of course, setting it up so the most powerful axis is to the fish isn't a bad idea, but it doesn't gain you very much.

At some point most builders will settle on a particular way of doing things (orienting the spine, finding the straightest axis, etc.) and then for the sake of consistency, stick with it.

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