I don't mean to sound a few pickles shy of a full barrel, but what is the straightest axis on a blank. I've not seen a bent blank, or at least one that bends in one direction. When I built two kistler blanks I won on @#$%&, there was an ever so slight roll in the blank that could be seen only by looking down the blank and paying very very close attention. I've also got a 10' 5wt rainshadow blank that when put together and rolled around in hand, will droop down noticably enough on the weak side of the spine. but it seems straigt enough when rolling it on a level hard surface. What's the straightest axis?

I'm guessing you didn't read the recent RodMaker article on how to easily find the straightest axis.

Most any blank will have a natural curve or warp. Affix the butt so that it is supported at two points about a foot or so apart. Try to get it reasonably level. Put something just beyond the tip for reference. A piece of graph paper on a card stock works well. Now rotate the blank and you'll see the tip travel in a circle. The high point on the circle will be very close to the straightest axis of that blank.

Rod blanks often contain minor crooks along their length too. But you're still going to find that when you do the above, the point when the tip reaches the highest point on its circular path is going to be pretty much in line with the straightest overall axis of the blank. You'll also find that the stiffest axis of the blank will generally be along that same axis.

The "effective spine" does not have a "weak" or "strong" side. The softest and stiffest axis of a blank are rarely opposite each other. The effective spine is understood to be the outside of the curve when the blank has been pressured and allowed to come to rest (OSCAR - Outside of Stressed Curve at Rest). It will not generally be along the straightest axis but it will generally be the softest axis.

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Here is something else you can try if you don\'t trust your eyes. Put the butt in a holding device and hang some weight from the tip. As you rotate the butt you will see the amount of deflection changes as the blank revolves. When it reaches the LEAST amount of deflection put a mark on the top of the blank. This will almost always be the straightest axis.

The thing about using the straightest axis is that because it puts the most power into play against the lure or the fish it seems IMO to provide the best sensitivity and quickest response.

Or, you can roll it on a flat surface and see the tip going up and down, also put a piece of tape around the blank, take it outside - good light - and look from the butt out to the tip, turn it and watch the tip move, mark in the up position.

Bill - willierods.com

Suppose I determine the straightest axis for each of the sections of a four piece blank. When I assemble the sections I fear that not all the ferrules are truly centered, which would result in a rod with a varying degree of zig-zag or cast-off rather than the straightest configuration possible. Is there any way to easily, quickly, and still accurately determine the straightest axis of the ASSEMBLED blank before affixing components and turning it into a rod?

If the ferrules are that far off, you might want to swap it for a better blank. Or, you can just turn the sections by whatever slight amount is needed to bring everything back into straight.

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