I am building my first rod using a Winston 6 wt 9 ft 2 piece rod blank. I have two books "Start to Finish Fly Rod Building" by Flex Coat and "Rod-Building Guide" by Tom Kirkman. The technique that I am using to find the spine is to hold the blank section at an angle while applying pressure and rolling the butt end on a smooth surface. The books have conflicting info. on marking the spine. One book says to mark the spine on the inside of the curve and the other book says to mark it on the outside of the curve. Which book is correct?

The second question that I have is in regard to finding the spine it self. The blank seems to have two natural positions 180 degrees apart when I roll it while holding it an angle and applying pressure. Which position is the spine?

Fred

The most dominant one would be considered the "effective spine." One good way to fine the most dominant position is to set the end of the blank on a marble and the press straight down on the tip. Do this several times and you should find that it will flex to the same spot a majority of the time. The outside of that curve is marked as your effective spine. Keep in mind that this is just a reference point for a particular position, as the spine is not a physical thing, just an effect.

On short stiff butt sections, consult the FAQs page for a reasonable method of dealing with these.

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Tom,

Thanks for the response. I will try your guidance on finding the spine. However I am still confused. I have two sources that say to locate the guides on outside of the curve. All sources say to locate the guides opposite the spine. Your advice indicates that I should place the guides on the inside of the curve. Am I missing something?

Fred

Fred,
You might want to consider locating the spine dynamically. To do this put the butt of the blank on some stable surface and hold it there firmly. Then deflect the tip straight down and then release it. If during the blanks oscillations up and down the tip tends to move in an elipse then it is not oscillating on the axis of the spine. Rotate the rod in small increments and continue to deflect and release it until it oscillates straight up and down. When it oscillates straight up and down it will be oscillating on the axis of the spine.

What does putting them on the outside of the curve supposedly accomplish? Did the authors mention why they advised what they did?

I don't advocate any particular spine orientation. You certainly can't make a rod stable (resistant to twist) by any particular orientation of the spine, although such is one of the oldest myths in all of custom rod building. All rods with the guides on top will be inherently unstable under load while any rod where the guides are located on the underside of the rod will be inherently stable under load.

On Emory's "dynamic" method for spine location - the act of casting is better approximated by a single deep flex, rather than setting the rod oscillating up and down, which is does not do on any actual cast. But I don't think it matters very much and the two won't be more than a few degrees apart. Have at it, either way.


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Tom do you have a new book out? The one titled Rod Building Guide didn't seem to have any specific recommendation for spine position. Did I miss something???

I've only done the one book. I did not recommend any single spine position because I didn't want to further the myth that there is a correct or incorrect position for spine orientation. So, I spent the chapter discussing what causes the spine effect and how various positions might change a rod's performance characteristics. Even so, such changes or differences will be subtle on most rods.

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Just my own opinion. I see the spine as having an an effect on the casting ability and accuracy function. I believe that if the spine is located on the casting plane of the individual's style of casting, they'll be able to cast more accuratley. ( sorry, my spelling leaves a bit to be desired). As far as fighting fish goes. once the rod is under a heavy load, then the position of the guides take over. As I said that's just my opinion after 30 some odd years of listening to all of the arguments about the effect of spines, not to mention countless seminars and demonstrations on the spine controversy. For what it's worth, Bob Vasko

I tested just that theory many years ago with my casting "machine." It took all human input and variation out of the equation and allowd for verbatim casts. I made literally hundreds of casts with it and with many, many different blanks and various spine orientations. I'm convinced that spine orientation does not affect casting accuracy.

What does affect casting accuracy, is grand deviation from the casting plane on a blank which has a high degree of curve or natural bend or warp. Put such a bend to the side, 90 degrees to the casting plane, and you can measure the distance that any lure or weight will be thrown off to the side of the intended target. Granted, it's only inches, but it's there and is repeatable on every cast.

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Holy cow. You guys are scaring a first time rod builder. I thought that I had a simple question. My intention is to go with Tom Kirkman's advice since the rod blank has two spines then I don't think I can go too wrong by placing the guides on either side.

Tom thanks for the guidance. Your book and the input has been priceless.

Best Regards,

Fred

Don't sweat it. It's nice to know where the spine effect is and how it affects your blank, but no matter where you put it, any differences will be very subtle. Rod spine is a subject that rod builders should have some knowledg of, but it probably gets put way to high up on the list of priorities for many builders. Beginners shouldn't ever think that they're going to ruin their rod if they don't orient it in a particular location.

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