Cane shaft - spine question...

[HatchA]

So I'm thinking about arrows and I'm liking the idea of making my own using Tonkin cane.  I know that with "regular" shafts, the shaft flexes more down one side and less down the other, giving us the "spine of the arrow".  This is in relation to the inner and outer sides of growth rings etc.

Does cane have a similar complexity in that it is stiffer along one side than it is along the other?  Or (I'm thinking) the "spine" of the cane shaft depends entirely on the structure of each individual piece of cane?  I'm probably over-complicating things here but I think you get what I mean.

Steve.

[stringstretcher]

There is definately a stiff side to cane.  Put that to the strike plate.

[riarcher]

Using my indicator style spine tester I just had to do some testing. 

Seems the stiff sides are always 90 degrees from where the leafs / shoots come off the shaft.
Both sides are ussually very close in spine, but one side willbe just a bit stiffer.

I first started with some unfletched shafts cut to a comfortable 30" length with 145 gr. screw-ins and self nocks. Shafts were wrapped both ends with thread for reinforcement.
The set consisted of 45,50,55,60,65,70,75# spines (well within a pound or two.
In my 52# shootaround the handle bow I found that from 55 to 70# they all pretty much shot the same.
My first doz. (actually 11) I targeted 60# ended up with 60-64 spine in the center. I tested these without fletch and found that they all flew good except 1(?) and it didn't seem to matter if the stiff was in or out. Remember, the diff. is only like .015 (if that) deflection when comparing the two sides.
The one oddball has a long flat spot on it where one of the shoots came out and I think may be the problem. It's destined to become a short range flu-flu. 

Also found that by moving the point where I measured by as little as 1/2" could / would change things dramaticly and the relationship from one shaft to the other was far from consistant. At best, I'd like to think I've measure an (sorta) average more than specific. I'm not even sure how accuate my 60# average is because they all vary on the ends from shaft to shaft. I'm considering my measurements as referance more than anything. While I'm calling them 60# arrows,,,, are they? I don't really know. but they seem to work.
Looking at them visually (nock end, pile end, middle) the diameters are not consistant either.

If you're looking for a techniclly logical way to select accuate shafts of Bamboo,,, you may want to invest in a jug of Scotch before you begin. 

[HatchA]

A lotta stuff...

Wow man, thanks for all that!  I wonder if the 90 dgree stiffness to the shoots has anything to do with the growth in relation to the sun etc.

If you're looking for a techniclly logical way to select accuate shafts of Bamboo,,, you may want to invest in a jug of Scotch before you begin. 

Now that's not a problem   I'va a nice collection in my cabinet

[riarcher]

Hmmm, you could be right. I was thinking the primary wind direction. But who knows.

PS; I'm hoping someone will see this and fill me in on a sure-fire way of selecting. Preliminary straightening and spine checking is a PIA on these. 

[Diligence]

bump ---  I'm wondering about a sure fire way to spine cane/bamboo too?

Okay - I retract that.  I just managed to find a bunch of good posts with this good bit of advice from PeteC.  I think I will have to try this preliminary spining before straightening.

"Like the others said,there are a lot of differences between cane.  Something I've been doing the last year or so is ,cut your cane long,like 4'-4 1/2'.  After it is dry,Measure the deflection along the length until you find the desired spine.  I have 2 nails driven into a shelf board,26" apart.  Starting at one end, lay the cane on the nails, mark the location of the unflexed shaft, then hang a 2 pound weight from the center of the section your testing, mark the new location of the deflected shaft, then measure the distance the shaft deflected.  Example:  If the shaft deflects .45",then , 26 divided by .45 =57.78# of spine or, if it deflects .3", then, 26 divided by .3 =86.67# of spine.   This is handy, because with this method you can rough test the spine before straightening the shafts.  After testing a few of your batch,  you will have a good idea what diameter you need to fit your need. Then cut, straighten, and build arrows.  Hope this helps.  God Bless"