Bamboo Tips - Tips Area
Rod Design - Turnover Point

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I apologize if missed this in an earlier thread, but can someone explain "turnover point" for me?  What is that in functional terms?  How do you identify it in the taper or stress values of a taper?  (David Bolin)

Turnover pt is simply the point of maximum tip stress. It's the point where the stress curve turns or stops ascending. It is a point on a Garrison or Deflection graph ( not a rod deflection chart). It is of no value except to evaluate an individuals perception of a rod. It is one of the things we can alter with a taper. I just thought it would be interesting to see if people could sense it while casting...some can, some can't. I'm not suggesting that my test rods are of any value at all, they were just my way of establishing some criteria by which rods could be evaluated and stress curves put in some context that people could understand. No doubt there are better ways to do this. It's my naive way to answer the question, " what are the key components of a stress curve."

Or, "If I am looking at a stress curve can I tell if I will like the rod." There is nothing conclusive here, just another little step, I hope. The middle three rods, tip stress, are the ones that test this premise.  (Jerry Foster)

Does this turnover point effect how the line is traveling when cast and if so, how does it affect the line being cast?  Also, it is said that a hinge like Wayne incorporated into his designs, would enable an easier roll cast, how does this happen?  (Ren Monllor)

For me, the closer the turnover point to the tip the tighter the loops but I didn’t like the stiffness it imparted.

For what it’s worth, my new rod is a great roll casting rod without a hinge.  (Jim Lowe)

The further the stress from the tip: IE should throw a wider loop. No it will not effect Roll casting. Its not really a hinge as compared to Wayne's butt hinges it really a different thing here. (Gary Nicholson)

Cool!  Why didn't I think of that?  I suppose that has something to do with being an amateur.  I learn something new every day.

Of the 444 tapers in my research database, the average turnover point (peak stress) is 14 inches from the tip top with an average stress value of 183,000.  That's using Garrison straight stress calculations.  The average values are 26 inches and 102,000 in FlexRod bent stress values.  That doesn't add much to the analysis on average, but the difference between the peak straight and bent stress points can be significant depending on the taper design.

I've added the Turnover point values to the FlexRod statistics view.  I'll try to post the new version for download in the next day or two.  Here's a few Payne tapers with Garrison style stress values: