Bamboo arrows fatiguing?

[Tommy D]

Does anyone notice bamboo arrow spine reducing/ changing over time? And if so is it a sort of slow continuous process or does it suddenly happen?

Do wooden shafts fatigue more or less than bamboo?

[bjrogg]

I haven’t used bamboo, but not to my knowledge.

Can you explain what is happening to make you think arrows are becoming weaker?

Bjrogg

[Tommy D]

Well I had a set made for me that were supposed to be spine matched and over time I felt some arrows were flying differently so I checked their spine on my home made spine tester and there is quite a wide range!

[Pat B]

I've never noticed any loss of spine with well seasoned cane arrows.

[Tommy D]

Ok good to know - maybe I just wasn’t paying attention to start with and they were always out of whack!

[gutpile]

cane and boo won't fatigue might increase as they fully dry ,check the spine on the weaker arrows by rotating the arrow to opposite side.. cane and boo can vary spine depending on side you test.. weird but true.. gut

[Allyn T]

Here is a quote from Khan's arrows website, "Here is the answer.  They DON’T change spines over time if stored under reasonable conditions.  What is happening is that because most static spine testers are not very accurate with measuring the shaft of an arrow with skin waves and irregularities, they will give you a different reading.  There is quite an art to measuring the static spine of bamboo shafts accurately"

[gutpile]

how many Indians had spine testers.. really ?.. think about it.. cane and boo are very easy to hand spine once you get an arrow flying right... not to mention both are IMO tolerable to spine ranges.. my cane can fly well at spines from 55 to 70 and even above.. ... gut

[Todd Mathis]

Well I had a set made for me that were supposed to be spine matched and over time I felt some arrows were flying differently so I checked their spine on my home made spine tester and there is quite a wide range!

I have bamboo arrows which have lasted for nearly 15 years...perhaps a few are even older.  I've never seen any spine test fluctuations, but there are several reason why you may be seeing this.
1-My first suspicion is that you are a better shot now, and so when some aren't grouping as they should, it is catching your attention.  If this is the case, and it actually was something I went through twenty years ago...congrats! 
2-My GREATEST suspicion is that most static spine testers simply don't work well with bamboo.  On bamboo arrow university, I put this up some months ago.  It gets a lot of traffic, maybe it will help...
https://khansarrows.com/best-way-to-measure-the-static-spine-of-a-bamboo-arrow/
Skin fluctuations, spine testers which don't allow for the other irregularities, and shafts which aren't quite round can cause issues.
3-I only know Tonkin River Bamboo.  If you are using river cane or others, I don't know enough to speak to that.  But if you are using Tonkin reed, and they are not perfectly straight, round, and with clean nodes, then you might upgrade the bamboo you are using...
If you learn something else, please let me know!  I'm always trying to inprove the knowledge base on bamboo arrow university...I'll owe you a beer!
Best regards.

[Tommy D]

Thanks for all the feedback. I measure spine with a home made tester using a calliper and a 2 LB weight made of a coffee jar with rocks in it! I do zero it each time so I take out any wiggles and bumps from the bamboo. Have definitely noticed that it does have a wide range of spine tolerances and I am aware of how much form can affect arrow flight.

I do also agree that “Traditional People’s” certainly did no formal spine testing. I am also reasonable aware out of a mix match of arrows that I have how each one will fly ... but it was more a curiosity that a supposed “matched set” should have such great spine variation.

I will keep an eye on them and see if they change further.

[Pat B]

When working with raw bamboo or cane arrows, whether it be raw hill cane, raw switch cane or raw tonkin "Martha Stewart" tomato stakes, the nodes lay on top and under the shaft as it sits on the bow. Of the other two sides you put the strongest spined side against the bow. This is how I was taught to build cane arrows from Art Butner, one of the best cane and shoot arrow builders I've ever known. Another thing that Art always held as gospel is to use well seasoned shafting, not just dry shoots and canes.
 Another thing I do is make my arrows longer, 29" to 30" for my 26" draw. In my experience this allows the arrow to get around the bow easier.
 There is a lot that goes into building arrows from raw cane or shoots, from their seasoning, straightening(not necessarily as straight as you'd think), spineing the shafts, knowing the bow these arrows will shoot from and considering all aspects of that bow; degree of center shot or not, handle and grip style, draw weight at intended draw length and the shooters style of shooting. Another thing I don't think some folks consider is the amount of natural taper in each cane or shoot shaft. It all goes into making good shooting arrows.
 IMO, arrows are way more complicated to build and more important than most folks give credit to. To most, the bow seems to be the critical part of the archery set up. In my mind it isn't, it is only a part of the equation. If the arrow is not set up for the bow, the shooter and the style of shooting it most likely will not shoot consistently.
 All that being said, if the shooter's style of shooting, draw length, grip, anchor and release are not consistent, the same with every shot, ones shooting will not be consistent. Also, complete concentration with all these aspects and knowing where the arrow WILL go(picking the "spot") and not just shooting at the target, your shooting will not be consistent. It's not just slinging arrows but so much more.

[Mesophilic]

I haven't noticed wood or bamboo losing spine but I swear they break in.  A fresh set of shafts just seem to fly a little different for me until I've shot them a number of times.

Might just be in my head or a subconconcious act on my part.  I've tested it by shooting a few fresh shafts with a dozen older ones and the newer ones group different for a while, even if I don't look at the shafts when I nock them so I have no idea which I'm shooting.

[Pat B]

Are you tempering the cane after you straighten them? I use our gas cook stove for straightening shafting. For the tempering I start at one end and rotating the shaft over the flame until I see a bit of color and move down the shaft a bit while rotating until I reach the far end. Be careful of steam coming from the far end. After tempering I lay them on a flat surface to cool completely. After they've cooled (I usually wait a day) you may have to do a bit of re-straightening with heat but after that the shafts should stay straight and stable.