I 'm in the process of building a rainshadow rod, RX7 graphite (CB66MH 10-20). The problem is that when I go to mark the spine I end up with two didtinct spine. I take a break and try again with the same results. What should I do?

TIA

Lou

Lou,
I'd bet that most on here build on the straightest axis and not the spine. I'd encourage you to do that instead. There's a good article in the most recent RBM that details this.

Happy Holidays,
Robert

Feel each spine. One will be stronger than the other. When you find that one that is strongest, build on that one.

Kevin

I'd vote for the straightest axis! Robert, what is RBM??

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!!

Sorry Mike, RMM. Too much Christmas with the kido and family.

I'd also go with the straightest axis and disregard the spine.

However, if you still want to find the effective spine, try sitting the blank butt on a marble and then pressing down on the tip. Mark the outside of the curve it forms. Do this a few times. Most likely, it will spin to the same mark each time as one will be more dominant than the other. That will be your effective spine.

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Go with the effective spine, being the one with the "softest" bend, or the most bend. Ton's marble trick is a good one if you don't have a Renzetti spining tool.

Uncle Russ
Calico Creek Rods

If you hold the blank horizontally and pull straight down on the tip, when you find the two "relaxed states" of the blank, if they're 180 degrees apart, aren't the two spines located at 3 and 9 o'clock? Thanks.

No, the spine isn't a "thing." It's not located anywhere. The Effective Spine is referenced as the outside of the curve when the blank has been pressured and allowed to roll into position. It's just a reference point, not an actual thing.

Remember, the spine isn't a physical thing - it's an effect created by several manufacturing anomolies.

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Guys,

Tank you very much for educating me on the spine.

Robert, Can you please give the RMM Issue that covers building straightest axis and not the spine? I need to learn how to do that.

Kevin, I was not able to tell which one was stronger. The gentleman that taught me told me that build on the stronger, I don't know if is the lack knowledge or that the spine were so close that I wasn't able to tell.

Tom, I Used the technique that you mention but I was getting different results, about 50/50. ( maybe me, maybe the rod)

Ross, I guess I need to invest in one of those tool. What say you?

Tim, You are correct they are located 180 degree apart.

Now for an update.

I mock-up the rod, guide and everything put a load in the rod maybe a one and half pound, guess what? The rod broke. Was this my fault?

Maybe, maybe not. A pound and a half is a pretty good load for say, a light bass rod. Not much for a powerful striper stick or saltwater rod. Return it to the manufacturer and let them determine the cause.

The spine is referenced as the outside of the curve formed when the blank is pressured and in the curve that represents the softest axis.

To build on the straightest axis, which most commercial manufacturers and many if not most custom builders do, just sight down the rod and find the straightest axis. There will probably be a slight curve in the blank and you want that upward (tip and butt high, belly low).

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