Hello All,

I'm new to this site and a first timer in building my own rod. I've modified dozens before and now just taking it up to the next level.

I recently came into possesion of a Lamiglas IM700 IMC845 Blank. I've heard of many ways to find the "spine on a blank, but from trying it out, it seems that there are TWO spots where the rod tend to have a relaxed curve. I've also tried to look down the blank to see if i could find the straightest angle, but have yet to find it.

How would i go about finding the straightest angle and what does the two spots where the rod tends to "jump" mean?
Which of the two techniques Straightest angle or Spine is the better way?


Thanks

---~ <*)))><{

I don't know anything about a "straightest angle." Do you perhaps mean, "straighest axis?" That's easy to find - just sight down the blank until you have what appears to be the straightest possible alignment. Or, support the butt at 2 points about a foot apart and rotate the blank. The tip will travel in a circle. When the tip is on the highest point of the circle, that will usually be along the straighest axis.

If you would rather work with the spine, stand the blank butt on a marble. Now open your palm and press straight down on the tip and let the blank flex and come to rest. The outside of that curve would be referred to as the effective spine.

Due to the many manufacturing anomolies, involved, blanks often have more than one spot where they will settle in and not want to move (you are not looking for where the blank "jumps"). But the dominant one is usually found by the method above.

................

Leo for a first timer you have done a very good job. Many highly experienced builders will notice two planes on that particular blank when performing a bend test as described. If the blank is observed to be straight by sighting and rotating while watching for tip movement place the guides on the same plane with the dominant Jump to or Lock up position. If the blank is determined to by bowed to a distracting curve, as described above by Tom, then position the blank where the bow in the middle of the blank is down and build a spiral wrapped rod.

Guys, Leo is a very knowledgeable Collegiate Bass Fisherman, who is interested in the performance issues of bass rods. I think he found this site by while seeking information on increasing the quality of his tournament rods through Tackle Tour. He had already started to modify his reel seats as per Rich Forhan' instructions. I talked to him for a short time on the phone and know he will bring just as much to this board as he takes!

Leo, welcome and please invite some of your fellow NCAA competitors to this site.



Edited 1 time(s). Last edit at 10/21/2008 03:38PM by Bill Stevens.

I'd recommend that instead of your hand, you use the cap of a pen. That eliminates the friction caused by your skin or the softness of your hand.

Many blanks show more than one effective spine. A test of this is to place the tip of the blank on a flat surface, make a ""V" between your thumb and forefinger and place the butt in that "V", and press on the rod about halfway down. The blank will roll or jump so that it's softtest side is on the inside of the curve - that's the inside of the effective spine. Mark it with a chalk pen. Now exactly reverse the rod, with the butt on the table and the tip in the "V", and bend it again. Most times, the same soft side and your mark will again be on the inside curve. Sometimes, it won't.

When it won't, we build so that the effective spine is the one we marked with the tip on the table.

Uncle Russ
Calico Creek Rods

Russ could you provide a "link" or secondary reference that explains fully what you are describing in your post? I am sure that the new builders, as well as a few of the old ones, would like to know the origin and more details of your information.

I would agree with those above about building on the straightest axis but if a builder believes that they should build on the spine there is ,in my judgment, a better way of locating it dynamically as opposed to statically ,and there is also an explanation for some of the odd locations where the spine often appears.
If you lock down the butt of the blank and deflect the tip of the blank down a few inches and then release it the blank will oscillate up and down. If the oscillation tends after a few oscillations to form an ellipse then the blank is not osillating on the plane of the spine. Rotate the blank a few degrees and deflect and release it again and continue this until the blank oscillates straight up and down. When it oscillates straight up and down it is oscillating on the spine or neutral axis or plane.
There is what mechanical engineers call an N1 to N2 axis or plane (Nuetral) and an S1 to S2 axis or plane (Stiff ) that run through the blank. S1 and S2 are 180 degrees from each other and the N1 and N2 are also 180 degrees from each other. And the N1 to N2 is 90 degrees from the S1 to S2 . What makes it very often appear that this is not the case, that the two stiff planes and/or the two nuetral planes are not 180 degrees apart or the S1 to S2 or N1 to N2 planes are not 180 degrees apart, is that they do not cross in the exact center of the blank. They are still 180 degree apart but where the S1 to S2 and the N1 to N2 planes cross is offset from the center of the blank. This offset, depending upon how much offset there is, will make it feel like the stiff and neutral planes can be almost anywhere. There can be a variety of causes for this including the blank not being perfectly straight. This is something that you might want to keep in mind when locating the spine on blanks.

Wow, you guys ROCK.

I'll definately have to try these techniques.

Once i get it all put together i'll post a few pics.

Thanks again


Oh, and Bill, let Lance know that i'll be making my order quite soon =)