Re: Made in Korea
[Bulletin Board]
Posted by GES on 20130522 12:22:32
in reply to Re: Made in Korea posted by Morsie on 20130521 18:59:24
Peter,
That deep dished arbor on the SAGE reels is one of the very good features of those reels, and I have several times made that point, when talking with Jamie Lyle at local fly shop shows (California Fly Shop); he's a SAGE rep.
A thin walled flat tubular arbor (like a pipe) is an unstable structure (for very thin walls) because flat surfaces can easily buckle.
By dishing the arbor, toroidal style, SAGE has used an anticlastic (saddle) structure which is inherently more stable than a flat surface (to buckling) it's not as stable as a synclastic surface like an egg shell, where the center of curvature is always on the same side of the surface. With the SAGE arbor, the crosssection of the spool, in the rotation plane of the spool, is in the center of the spool (inside the toroid). At right angles to the rotation plane, the center of curvature of the crosssection is outside the spool; not inside.
You can prove, that with any anticlastic (saddle) surface, there is always (at least) one direction in which the curvature is zero. That's the direction, where the center of curvature passes from inside the spool to outside the spool.
That is the reason that anticlastic surfaces are not as stable as synclastic surfaces; but are more stable than flat surfaces. The length of the zero curvature straight line paths in the SAGE spool is very small, so the chance of a buckle is microscopic. Well they also don't make it thin enough to get anywhere near buckling. But they can make it thinner than a pure cylindrical arbor can be made, for the same strength.
And yes; there's no holes in it.
George 
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