i think i understand.  a rodmaker finds the spine of the rod.  this is the Stiffest/fastest direction a rod bends?  so that is where the guides run?  

 

so theorectically, say a fast action rod might not be the exact same fast action if the rod is bent in a different orientation?

Kinda.  The spine is a line down the blank that has just a little more or a little less resistance to bend.  Its subtle and varies by blank.  I've had blanks that had a spine that a blind man could see just under the natural weight of the rod.  I've had blanks that you couldn't find a spine at all.  While technically you're right that there is a difference in the bend (and thus the action) if you bend it along the spine or perpendicular to it, the variation relative to the total power of the blank is not that much.  To find the spine, you're only flexing the blank about as much as a light lure would just hanging there.  When you cast or set the hook you're adding a lot more force than that.

 

Also, some builders/companies ignore spine entirely and build on the straightest axis.  

There are several yt vids on how to find the rod spine.

 

Also..casting rods are generally built w the guides on the spine. 

not interested in finding the spine.  or building any rods.  just wondering about the mechanics of it all.  

Interesting as spine in arrows is very important. Spine is a measure of deflection. Most good arrow builders will ensure that all arrows are fletched similarly with the stiffest area of the spine oriented in the same location (**** feather/vane oriented to the stiffest side). So I would think that orienting the guides to the stiffest side of a rod (every rod) would yield a similar result. But how much of a difference that would make in a tapered blank (rod) vs a straight shaft (arrow) is probably not worth losing too much sleep over. I would doubt that running the guides over the stiffest or the least stiffest spine orientation in a rod would change the action from a XF to F action, etc. An archer needs as much consistency as they can get arrow-to-arrow. And even then, only archers who are highly skilled are accurate enough to see a real difference in accuracy by matching fletching location according to spine orientation. Unless anglers were using six exact MHF rods fished exactly the same, I would think it would not matter. And even if one did, they probably would not recognize a difference. 

26 minutes ago, BrianMDTX said:

Interesting as spine in arrows is very important. Spine is a measure of deflection. Most good arrow builders will ensure that all arrows are fletched similarly with the stiffest area of the spine oriented in the same location (**** feather/vane oriented to the stiffest side). So I would think that orienting the guides to the stiffest side of a rod (every rod) would yield a similar result. But how much of a difference that would make in a tapered blank (rod) vs a straight shaft (arrow) is probably not worth losing too much sleep over. I would doubt that running the guides over the stiffest or the least stiffest spine orientation in a rod would change the action from a XF to F action, etc. An archer needs as much consistency as they can get arrow-to-arrow. And even then, only archers who are highly skilled are accurate enough to see a real difference in accuracy by matching fletching location according to spine orientation. Unless anglers were using six exact MHF rods fished exactly the same, I would think it would not matter. And even if one did, they probably would not recognize a difference. 

 

A bow is putting a LOT more energy into an arrow than a fisherman into a cast.  And as you say, consistency in archery is key. Arrows could all be spine up, down, left, right and as long as they are the same it makes less difference (in a well tuned bow).

 

If anyone was interested, you could use the common cents system to measure the difference by locking in the rod butt and measuring it spine up, spine down, and spine to the side.  In my practical experience there is minimal difference in rod action doing it that way.  Sometimes you'll feel it in the rod's feel while casting if there is a pronounced spine.  With fly rods with a longer power application stroke you might feel a little bit of a twisting motion if the spine is off by 90 degrees and you have a smooth/straight stroke.  For that reason I always put the guides on the inside bend of the spine for a smoother line pickup off the water.

 

And if you want to get really technical, depending on which side of the spine you'd build on it could make the action faster or slower.  If you put the guides on the inside bend, then the tip would flex a little touch more for a given bend.  On the outside bend it would be slightly less.  In the first case that would lead to a sharper tip angle and a faster measured action.  The opposite would be true for the other case. But we're talking about minute differences that make no difference to an angler.

 

Its difference without distinction.

I do a lot of sweeping with my retrieves and when bringing in fish ... Im probably missing out on that sweet sweet spine action

Spine is an outdated, debunked theory from the 80s.  WAY over thought and discussed. It’s nothing more than a manufacturing anomaly of a tubular shape. Many if not most current builders build on the straightest axis because no blank is arrow straight. Materials, dimensions, components and guide spacing are the keys to a quality rod.  

Just now, garroyo130 said:

I do a lot of sweeping with my retrieves and when bringing in fish ... Im probably missing out on that sweet sweet spine action

This fact that a rod is not casted or fished on a single plane is one of the reasons spine is irrelevant. 

6 minutes ago, Delaware Valley Tackle said:

Spine is an outdated, debunked theory from the 80s.  WAY over thought and discussed. It’s nothing more than a manufacturing anomaly of a tubular shape. Many if

Well, you just ruined half the internet rod building experts opinions.?? I will admit, I thought it was a valid concern but mainly overlooked in mass production.  

37 minutes ago, Delaware Valley Tackle said:

Spine is an outdated, debunked theory from the 80s. I don't agree with this, please share the evidence of debunking.

 

  WAY over thought and discussed. I agree with this

 

It’s nothing more than a manufacturing anomaly of a tubular shape. Many if not most current builders build on the straightest axis because no blank is arrow straight. This is debatable, as many builders certainly still do

 

Materials, dimensions, components and guide spacing are the keys to a quality rod. 

This fact that a rod is not casted or fished on a single plane is one of the reasons spine is irrelevant. ABSOLUTELY agree with all this

 

I'm not entirely convinced that the difference is discernible to a human whether on spine or straightest axis or any hodgepodge between, but Gary Loomis builds on the spine and his explanation why does make sense to me. Just search Gary Loomis rod spine, he blames the physics of casting for why he does it and says 90% of the time the spine is oriented the same as the straightest axis anyway.

 

Mass produced rods are almost always guaranteed to be built on the

 

 

 

Straightest axis, people always look down a rod and straight rods sell better than spined rods. But I've ended up with some nonspined crooked sideways rods before... I build now haha.