Where should I locate the spine on my rod blank in relation to the guides?Updated 3 years ago

There is no wrong position to locate your blank's spine. Where you do put the guides in relation to the spine, however, will result in certain performance characteristics being either enhanced or reduced.

There are three viable options as to where to locate the spine:

1. Spine on top - This option gives a bit more power on the forward cast but a bit less for line lifting (fly) and fish fighting.
2. Spine on bottom - This position puts the spine into strong play (better tracking) on the forward cast and gives you slightly more power for lifting line off the water (fly). Opponents of this method say this position will lead to rod twist when fighting a fish. This is not true, however, as guide position alone determines rod stability. (More on this topic can be found in the next question.)
3. Spine on stiffest axis - Disregard spine and locate the rod's stiffest axis so that the fish is pulling against it. A blank's softest and stiffest axis are not necessarily 180 degrees opposite each other. This usually locates the blank's natural bend in such a way that the butt and tip are "up" and the belly of the blank is "down". This puts the maximum amount of power into play for fish fighting but may result in slightly less casting accuracy/tracking.