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How to find spine across multi-piece blanks
Posted by:
Craig Snapp
(---.hlrn.qwest.net)
Date: October 26, 2022 09:50PM
I'm trying to find the best, most accurate way to find the spine across multi-piece blanks?
Thanks very much! Craig Snapp Re: How to find spine across multi-piece blanks
Posted by:
Ron Weber
(---)
Date: October 26, 2022 10:00PM
Why? Re: How to find spine across multi-piece blanks
Posted by:
Tom Kirkman
(Moderator)
Date: October 26, 2022 10:16PM
You'll have to do it piece by piece, then assemble in alignment and check again. Shorter sections can make it difficult for sure.
Then again, you may wish to consider the science and build that way... [www.rodbuilding.org] ........... Re: How to find spine across multi-piece blanks
Posted by:
Herb Ladenheim
(---.net)
Date: October 26, 2022 10:25PM
Craig,
Like Tom says: Spine section by section. If S1 is too stiff to spine by its self - assemble with S2 and spine as one. Spine S3 and S4. Assemble the whole blank and spine as a one piece. The odds are good that S1 and S2 will influence S3 and S4 to the extent that the assembled spine will be "off". If that is the case - you will then remark the spine when fully assembled - probably only S3 and S4 will have to be re-marked. Herb Re: How to find spine across multi-piece blanks
Posted by:
John DeMartini
(---.inf6.spectrum.com)
Date: October 26, 2022 11:22PM
I would assemble each section so that the blank is straight when looking along the length of the blank and build on the straightest axis.
. Re: How to find spine across multi-piece blanks
Posted by:
roger wilson
(---)
Date: October 27, 2022 03:26PM
Ditto on John's comment:
Take each piece of rod blank and roll it across a dead flat surface. Make note of and mark any sections that aren't straight and mark the side which indicates a bend. Then, take each of the pieces and align the pieces using the markings on each piece to assemble a rod that is the straightest possible rod that you can assemble with the pieces that make up the rod. Do, a final mark up of each rod piece so that you can maintain that alignment down stream through the build and after the rod has been complete. Just forget about the word spine when it comes to rod building and move on to things that are important. Best wishes Re: How to find spine across multi-piece blanks
Posted by:
Michael Danek
(---.alma.mi.frontiernet.net)
Date: October 27, 2022 04:40PM
Just forget about the word spine when it comes to rod building and move on to things that are important.
Yup Re: How to find spine across multi-piece blanks
Posted by:
Craig Snapp
(---.hlrn.qwest.net)
Date: October 27, 2022 04:41PM
Thank you all very much for great info!
Cheers Craig Snapp Re: How to find spine across multi-piece blanks
Posted by:
Chris Catignani
(---)
Date: October 28, 2022 08:33AM
Tom Kirkman Wrote:
------------------------------------------------------- > Then again, you may wish to consider the science > and build that way... > [www.rodbuilding.org]. Tom...Great article...also a great lesson on how to test. Q: How do you find the strongest axis? Re: How to find spine across multi-piece blanks
Posted by:
Tom Kirkman
(Moderator)
Date: October 28, 2022 08:50AM
You can do it by hand feel, or you can attach a weight to the blank tip held against a wall mounted scale or tape, and rotate the blank until you record the least amount of deflection. That will be the stiffest, strongest axis. It is generally going to be along the blank's straights axis, or very, very close to it.
............ Re: How to find spine across multi-piece blanks
Posted by:
roger wilson
(---)
Date: October 29, 2022 01:00PM
Craig,
If you really want to find the spine on any thing, and or any length - you can use rod rests to do a precise job. Here is a picture of some of the very first rod rests that I made a very long time ago, but the fit and function still work very well today: [www.rodbuilding.org] To check for the spine of a blank of any length, simply take 3 of the rod rests pictures above and remove the bar with the single bearing on it from the rod rest. Then, take one of the three rod rests and turn the remaining bar with the two ball bearings on it - upside down. When using these rod rests, I have a board with a slot in it that will accomodate a 1/4 inch carriage bolt with the head of the bolt on the underside of the board with the head of the bolt resting in a widened slot on the underside of the board to allow the bolt to slide up and down the board without touching the rod bench. Now, to use the setup, take the two rod rests with the double rollers and set the rollers at an equal convenient height. Bolt them down so that they are 2-3 feet apart. Then, take the 3rd rest with the double rollers facing down and bolt it 1/2 way between the two other rod rests. To use the spine finder just made, simply lift the roller bar out of the way on the middle rod rest and lay the rod blank on the rollers of the two outside rod rests. Place the rod blank in a part of the blank that you would like to check for the presence of a blank spine. Then, place the bar with the rollers on the underside of the bar, back on the rod uprights and press down, until there is a significant bend in the rod blank. Tighten the thumb screws. Now, simply rotate the blank a few times checking to see if it stops in the same spot evry time. iIf it does stop in the same spot every time you have found the spine, so take a pice of thin (like 1/8th inch wide painters striping tape to mark that side of the blank to mark the spine. Then, repeat the same thing several inches or even a foot or more in a couple of different spots on the blank to see if the spine changes as one goes up and down the blank. Don't be surprised if you do find a change. But go with the spine that you find that is most pronounced. Then, repeat for other blanks or other blank sections. Once the rod rests or spine finder is setup, you can find the spine on a blank in a few seconds - mark the blank and then move on to the next one. If one is serious about using the spine - you can have the spine finder setup, any time that a new shipment of blanks or blank pieces arrive. Then, just go ahead and go through the entire shipment of blanks - placing a piece of tape on the blank - marking the spine. --------------------- But, as ai said earlier, I personally disregard eny part of spine, and or spine finding on a rod blank when building a new rod. Rather, i simply build on the side of the blank that is most straight. Sorry, only registered users may post in this forum.
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