Re: accurate rods?
Posted by GES on 2019-01-07 10:20:41
in reply to Re: accurate rods? posted by Ted Shuck on 2019-01-06 11:25:08
|The cheapest rod blanks are usually rolled from a single flag that is cut to some specific National secret flag shape to give the rod the behavior they want.|
It is highly likely that the line where the rolled flag ends, is the stiffest direction of the blank. The inner flag edge is at a smaller radius, and has almost no effect on the blank stiffness.
So if you set the guides in a line along that outer flag edge,(assuming of course it is even a straight line), one side of the blank is larger in diameter than the opposite side, so the blank is not even left-right symmetrical so it is going to have some sort of a sideways bias to it.
A common method of "spining" a blank ends up identifying the softest, least stiff direction of the blank and uses that as the plane for the guides.
It's so long since I built a rod, that I've forgotten how I used to spine mine, but I believe I used the softest bend plane I could find for the guide plane.
I'm not even going to speculate how various manufacturers do it, because I don't want to accidently reveal somebody or other's company secret, but I bet they all have their secret ways to do it.
These days, I just let Rick Pope's experts build rods that I can afford to buy. And I'm sure there are other good ones too.
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