Rod Balank Spine argument.

[gstours]

   Here,s a blip I copied to show us,  the public, how we can be misled in many ways.


"Almost everything written about rod spine in the past 30 years has been a myth. Not once has anyone offered evidence that the spine is at all important. And the laws of physics rule that it is not. At least not as important as the torque created by the lever arm effect of the guides."

"What you do with a spine finder in no way approximates what will happen when casting or fighting a fish. In both those instances, the rod is loaded by a line pulling through the guides"

"One thing to keep in mind about the rod spine thing, is that those folks who once said spine was so important never offered any evidence or proof that it was - they just said it was and a lot of folks believed it. Nowadays, they ask those of us who have said all along that it's highly overrated to offer proof of our viewpoint. Well, I'm still waiting for them to prove theirs - they never did and still haven't. It was always a myth. Nothing wrong with spining your rods, but you cannot make a rod stable or make it cast more accurately by doing so."

"The earliest books on rod building also mentioned spine, and all stated flatly that it was of no consequence in rod building. It's not an important aspect of rod building and only became thought of as being so in the mid to late 1970's. But every author that thought it important never stopped to consider that when we fight a fish, we do it with a line that is pulling through a series of guides on the rods. And not a single one of those authors ever bothered to string up a rod with guides, and then load the blank that way. They just flexed or loaded the blank by hand - something which a fish does not do. When we fish, the rod is loaded by means of a line pulling through guides, or small lever arms, if you prefer. And that's exactly why the major argument for any particular orientation of rod spine - that of using it to create a stable rod, is completely flawed."
   I know this may be a controversial topic,  butt its good to stimulate the mind during the lockdown blews.       gst.

[gstours]

   NOTE;   this is a copy from a publication.   My Disclaimer gst.


I figure when a builder build a rod based on the straightest axis is when he is working on a crooked blank. If the blank is straight all axis are straight. Is there a need to determine the straightest axis?
If a crooked blank was not built on the straightest axis then it will be very obvious to the eye when the rod is completed.

There is such a thing known as a spine. Remember how a blank is built?
Flags of graphite "cloth" are cut and the wrapped onto the mandral. The axis which has got the most overlaps will be the strongest/stable under load.
If there is no spine then how come the blanks will tend to rotate back to one or two fixed positions everytime? (Procedure of determining spine)

Rod twist is created by the torque of the guides on top. Next time relax your hands (that's what I was trying to say) when you land a big fish on an overhead and see what happen. Have you ever felt the rod twisting on a spin set-up?

I agree no doubts abt that but I never felt it twisting with a splined OH outfit.

"Almost everything written about rod spine in the past 30 years has been a myth. Not once has anyone offered evidence that the spine is at all important. And the laws of physics rule that it is not. At least not as important as the torque created by the lever arm effect of the guides."

I totally agree to the law of physics but that does not mean that there is no such thing as spine or splining is redundant. However it only proves that guides under the blank will not have the torque effect on a spiral wrapped rod. Therefore eliminating rod twist.

"What you do with a spine finder in no way approximates what will happen when casting or fighting a fish. In both those instances, the rod is loaded by a line pulling through the guides"

Why not? As quoted rod is bent by a line pulling thru the guides? under such circumstances the blank will rotate back to it most stable position. Remember procedure of determining the spine?
Why spinning and spital wrapped rods will not twist is due to the law of physics again.
( guides under blank)

"One thing to keep in mind about the rod spine thing, is that those folks who once said spine was so important never offered any evidence or proof that it was - they just said it was and a lot of folks believed it. Nowadays, they ask those of us who have said all along that it's highly overrated to offer proof of our viewpoint. Well, I'm still waiting for them to prove theirs - they never did and still haven't. It was always a myth. Nothing wrong with spining your rods, but you cannot make a rod stable or make it cast more accurately by doing so."

"The earliest books on rod building also mentioned spine, and all stated flatly that it was of no consequence in rod building. It's not an important aspect of rod building and only became thought of as being so in the mid to late 1970's. But every author that thought it important never stopped to consider that when we fight a fish, we do it with a line that is pulling through a series of guides on the rods. And not a single one of those authors ever bothered to string up a rod with guides, and then load the blank that way. They just flexed or loaded the blank by hand - something which a fish does not do. When we fish, the rod is loaded by means of a line pulling through guides, or small lever arms, if you prefer. And that's exactly why the major argument for any particular orientation of rod spine - that of using it to create a stable rod, is completely flawed."
     All comments welcome.

[oc1]

That's very thought provoking Gary and it makes perfect sense.  Come to think of it, it is easy to find the spine on a rod blank.  But, can you find the spine on a blank that has been built into the rod?  Will the spine be in the same place if the guides and handle are stripped away?  Great post.

[the rockfish ninja]

   Here,s a blip I copied to show us,  the public, how we can be misled in many ways.


"Almost everything written about rod spine in the past 30 years has been a myth.

It would have been good to display your source. .....

https://www.rodbuilding.org/library/blankstrength.pdf

This article is from Rod Maker magazine and although it may seem negligible, it says after testing using the spine location added 6% greater deadlift strength before breaking. It states they use the spine location to find the thickest wall of the blank to build off of, giving it more strength.

6% may not seem like much, but it might be the difference between success and humiliating failure at the hands of a rod breaking deep sea beast.

[Rivverrat]

 



    This is a very cool / thought provoking statement & question. Far more so than some realize. Including the makers of blanks here in the U.S.
My ideas after testing & building a few rods does not agree with conventional wisdom in this regard, in some ways. However I will have to reply at a later time. Because I only have 2 days off to build the rods that need to get off my bench soon... Jeff 

[Swami805]

If you roll a blank on something flat like you would a pool cue to see if it's strait you'd find almost all have a slight curve or bend. That should be the spine with any luck. If you don't wrap on that curve the rod won't look right, either the guides aren't centered on the blank so they appear strait or they follow the curve and look crooked.  To me anyway I wrap a rod following that curve. I pretty much wrap all calstars and seekers which are pretty thick blanks, I don't know if all thin fresh water blanks are like that but the ones I've done had some kind of curve.

[kjdunne]

Do you put the guides on the inside or outside of the curve?  Just curious, I've not built any rods.

Kal

[steelfish]

If you roll a blank on something flat like you would a pool cue to see if it's strait you'd find almost all have a slight curve or bend. That should be the spine with any luck. If you don't wrap on that curve the rod won't look right, either the guides aren't centered on the blank so they appear strait or they follow the curve and look crooked.  To me anyway I wrap a rod following that curve. I pretty much wrap all calstars and seekers which are pretty thick blanks, I don't know if all thin fresh water blanks are like that but the ones I've done had some kind of curve.

[Cor]

We recently had a thread on a topic that touched on this, re acid rods.

https://alantani.com/index.php?topic=22222.msg385273#msg385273

I have very seldom been aware of the effect of the spline on a rod or then the twisting it is supposed to cause.   I have used the spline to determine if I want to cast or pull fish with the stronger side which on a conventional rod are on the opposite side of the rod.

On very strong rods I have noticed a twisting with a bent blank.    If I remember correctly the bend had been to either the right or left.

Just a final point, using the technique of rolling the tip of the blank on the floor it is not always easy to find the  precise location of the spline as it often has two points where it jumps to.   I then try to find the softest side, but how come we have two spots?

[ReelClean]

Do you put the guides on the inside or outside of the curve?  Just curious, I've not built any rods.

Kal

The theory is that the rod will "roll" to get the spine in line with the load, so depends on whether it is bound for overhead or underslung reels.  It might have a slight twist in the hands as it aligns itself under load.  How much it matters, IDK, but I always find the spine and bind the guides along it (for the very few rods I have built!)
cheers
Steve

Doh!, beaten to the post again!!   

[ReelClean]

We recently had a thread on a topic that touched on this, re acid rods.

https://alantani.com/index.php?topic=22222.msg385273#msg385273

I have very seldom been aware of the effect of the spline on a rod or then the twisting it is supposed to cause.   I have used the spline to determine if I want to cast or pull fish with the stronger side which on a conventional rod are on the opposite side of the rod.

On very strong rods I have noticed a twisting with a bent blank.    If I remember correctly the bend had been to either the right or left.

Just a final point, using the technique of rolling the tip of the blank on the floor it is not always easy to find the  precise location of the spline as it often has two points where it jumps to.   I then try to find the softest side, but how come we have two spots?

I have seen a technique where you hold the tip under your palm and support the blank on your palm  (above half way, closer to the tip).  As you roll the blank across your palms you will see the butt drop towards the floor at some point and show you where the soft side of the spine is.  Sometimes you might see two dips depending on how the blank was built and where you support it.

[Vintage Offshore Tackle]

I don't know my earhole from my elbow when it comes to the technical aspects of rodbuilding, but I do know that Swami805 builds the finest rods that I have ever seen, and has built more of them than anyone else that I know.  If he expresses an opinion on the subject, it is based upon extensive experience, and you can take it to the bank.

[Jeri]

I've read a lot of words and discussed the wisdom of the topic of spines in blanks, including those of professional blank builders, some of those opinions reflect this idea that the spine is not as influential as proposed, others more engineering orientated.

The first thing that I would disagree with in the opinion offered, is that the writer hasn't disproved the spine argument, just over-ridden it with another one. Not a deal breaker in itself, but just to highlight a line of logic.

I freely admit that I tend to base a lot of my opinions on the fact that we build a lot of long surf rods, be they 1 piece or multi-section, and this might be a clue as to why I stand by my opinion. A long rod will highlight or exaggerate all the attributes of a rod/blank, be they negative or positive, especially when compared to shorter rods/blanks to the analysis.

I use a lot of blanks built by some very specialist manufacturers, and pretty much in all cases, on unground blanks I can actually see the line of the overlap, which in most cases is very straight, and the whole purpose of precision cutting of the flags of carbon. This is not the case with a lot of mass produced items, where the overlap may spiral around the blank and sometimes worse. The point here is that to get the flag cut precisely to give that straight line is the theoretical optimum to achieve the original design. This will by virtue of the '+1 wrap' situation offer a section of the blank that is proportionally stronger than the rest of the circumference, this then leads to the spine.

This '+1 wrap' aspect can be very significant, on a 10 wrap blank, it could represent a 10% increase in strength across that zone, while on a thicker 20 wrap blank it would only represent 5% increase in strength. A reason why it is so easy to detect the spine on most blanks.

Building and using the blank with the spine in any position other than 12 o'clock and 6 o'clock, is also going to introduce a varying degree of torque in just the blank alone, as all these engineering aspects are judged from the center point of the hollow of the blank.

A point here is that any hypothesis needs to work and be applicable in all situations, whether on a spinning design or a casting design; otherwise the hypothesis fails.

Onwards to the next stage of the hypothetical rod construction, and the introduction of guides, and any proofs about torque need to work with all situations, casting standard guides, high leg guides and micro guides, as well as all the same situations for a spinning rod. And it is here that the 'proof' that guides induced torque fails, for in all spinning rod the rod is used critically in both the 12 o'clock and 6 o'clock positions during casting and despite in many cases high/tall guides being used there is no evidence of torque induced by the guides having any effect – unless te rod has been built 'off spine'.

The anomaly that has been cited is using the rotational effect of combined guides and reel operations on a casting style rod against load, to attribute the effect of torque, but this only occurs when reeling under load, so how much of this effect is due to the operational loads of the reel? And, perhaps not the guides alone? An example to slightly dispel the 'guides only' torque, is to be found in Interline rod designs, especially when used in a casting format – the rotational force is there as well – perhaps the reel under load is the key here.

So, in conclusion I would suggest that there is great importance to using the spine of the rod in either of the desired positions 12 o'clock or 6 o'clock, though either are not specific to only spinning or casting designs. Guide designs whether tall or low will have a small effect on casting rod designs, but not to the exclusion of all other design considerations.
One final aspect, curved rod blanks, these are basically defective, and any rules pertaining to them is a mis-direction, and only serve to cover up the problems associated with defective manufacture.

The above is only my opinion, however based on years of build rods, though the last 20 on predominantly long surf rods, and 30+ years as an engineer, looking very critically at angling designs, and 60+ years as an angler.

[Jeri]

We recently had a thread on a topic that touched on this, re acid rods.

https://alantani.com/index.php?topic=22222.msg385273#msg385273

I have very seldom been aware of the effect of the spline on a rod or then the twisting it is supposed to cause.   I have used the spline to determine if I want to cast or pull fish with the stronger side which on a conventional rod are on the opposite side of the rod.

On very strong rods I have noticed a twisting with a bent blank.    If I remember correctly the bend had been to either the right or left.

Just a final point, using the technique of rolling the tip of the blank on the floor it is not always easy to find the  precise location of the spline as it often has two points where it jumps to.   I then try to find the softest side, but how come we have two spots?

The choosing of spine to determine priority for casting or pulling is perhaps the right analogy. I've used the softer aspect when building surf rods for ladies, making the rod easier to cast. A purely comfort issue.

Twisting under heavy loads can be an aspect of which way the rod blank was rolled initially, though ir is only a very small influence. We did find this as an aspect when looking at Acid Wrapped surf rods, some blank manufacturers wrap the carbon in one direction, while other the opposite.

'Double Spines', I have found on some cheaper blanks, where possibly flag cutting and wrapping hasn't been as good as it could be, thus resulting in a near spiral of the overlap.

[Makule]

Aside from any theory, my only comment is that I have had rods built with the spline one way and others with the spline in the opposite side.  I know which side I prefer because I can definitely feel the difference in my hands as the rod tends to turn when the spline is the "wrong" way.