bamboo arrow making

[Todd Mathis]

recently posted a website on how to make your own bamboo arrows, tune them, etc.

[snag]

Under "Preparing bamboo shaft" in the red highlighted area for selecting a shaft for a 50# draw weight cut to center bow. This recommends going down to a 40-45# spines shafts. I have always found a stiffer shaft is required for a cut to center bow, not the opposite. They need to pass along accurate info. in order to best serve the traditional community. They go on to say that the 35-40# spine shafts at 38" are not a problem. Because when you cut them down they are 54#. So evidently they are determine spine by the standard way. "There is a standard for the measurement of spine which is the amount of deflection that a shaft will assume when loaded with a 2 pound weight mid-point between supports located 26" apart".

[macbow]

Snag, I'm still experimenting tuning with bamboo. But have found overall that the lighter shafts like 45 to 50 shoot well off of bows up to 60 pounds. If left at 32 inches.

Still new to matching shafts to different bows though. Bamboo seems to have some different rules.

[snag]

Interesting. How do they spine?  True to how they are listed? TheyIf not, how do you know what to order? On the site it says 35/40's at 38" will spine 54# at shorter length...? Why not just list them at a spine weight that is true by our standards?

[Todd Mathis]

Originally posted by snag:
Under "Preparing bamboo shaft" in the red highlighted area for selecting a shaft for a 50# draw weight cut to center bow. This recommends going down to a 40-45# spines shafts. I have always found a stiffer shaft is required for a cut to center bow, not the opposite. They need to pass along accurate info. in order to best serve the traditional community. They go on to say that the 35-40# spine shafts at 38" are not a problem. Because when you cut them down they are 54#. So evidently they are determine spine by the standard way. "There is a standard for the measurement of spine which is the amount of deflection that a shaft will assume when loaded with a 2 pound weight mid-point between supports located 26" apart".

[Todd Mathis]

I am glad to get that feedback.  Apparently your experience with center cut bows are different than mine.  But you are correct!  Bamboo arrows DO seem to have their own rules...  It has been my experience over many years of making, shooting, correcting my knowledge that the farther away the arrow is from center shot, the more it has to flex for paradox.  I picked off my quail with a center shot recurve.  Later, when I went to a "primitive" horse bow, with no cut whatever, I had to drop the arrow poundage down 10 lbs from what I would normally shoot to get the same aiming point.  That is when I could start picking off squirrels.  So, I do believe my information is accurate.  If you visit asian websites who shoot these, you will find that they agree.  But you are also correct, I do measure static spine witht he standard 2 lb weight.  but adjusting for dynamic spine is what bamboo arrows are all about!

[Todd Mathis]

Allow me to elaborate.  Bamboo, being a grass, has some sides that are stronger than others.  Since I shoot a 4 fletched arrow, I nock it up and shoot.  I found that sometimes the same arrow shot differently, depending on which side faced the bow, and which side was out.  I assume that this is probably an irregularity in the inner part of the shaft.  natural growth...whatever.  So, if they aren't grouping well, I simply adjust for dynamic spine by shortening them, or adjusting the head weight being the easiest way.  So, the trick to spining bamboo is to see how they group and then adjust the dynamic spine.  This is only something I have ever found in bamboo arrows.  Odd...I know... but anyway, they are very accurate, once you get to know them.  Glad to get your feedback.  Best regards.

[Todd Mathis]

great question snag!  If only we could get that!  How nice it would be.  But they come from China and I find that my supplier, while being quite honest, can't speak English or write it very well!  I would love to explain to him the irregularity, but I'm pretty sure that would be like speaking with my doorknob.  So, I simply adjust them and go from there.  I have often fantasized about importing them, spining them and selling them in accurately sorted groups, but alas...there isn't enough of a market...yet.  I guess it comes with the territory.  If I had to have exactness, I would stick with carbon arrows.  Bamboo offers too many other advantages, so I approached the problem another way.

[Todd Mathis]

another reason  to order the shafts lighter than you normally would is because you will be cutting them down several inches unless you actually shoot a 38 inch arrow.  This will automatically stiffen the spine back up closer to what you need.  Make sense?

[ozy clint]

I say this from a primitive view point- the easiest way to weaken the spine is to scrape the shaft. I've accepted that trying to make a set of matched for weight and spine bamboo arrows is wasteful of time and bamboo. It would take a forest of cane to find a dozen the same and I can't imagine the ancients wasting said resources when they were using them to survive. I pick a shaft that is too stiff, cut it to length then scrape it to weaken the spine until it shoots good with the point weight I intend to use.

Yes, this means each arrow is tuned individually and is unique.
Easy is going to the trouble of sorting through many many shafts to find a matched set.
Simple is making what you have work for you.
This is how I do it for my primitive setup anyway.

[Todd Mathis]

I weaken the shaft by leaving it longer and glueing on a heavier head.  I would be concerned about damaging an arrow shaft by scraping it, and I'd still have to spine it again, and then shoot several to see if it grouped with the other bamboo arrows in the quiver.  what do you scrape your shafts with?  sandpaper?

[Todd Mathis]

for me, if they group in a saucer sized group at 20 yards, they are spined well enough for me.  since I shoot with a thumb ring, if the arrow hits to the right of the group, the spine is too strong.  I just put on heavier head.  It the arrow hits left of the group, I put on a lighter head.  Since I number mine, it's easy to make a note and do that at home.  Since I order them in a bundle of 100 out of china, I always have more arrows than I could possibly shoot.  They cost about a dollar per shaft that way.

[BAK]

Todd, I'm not understanding what your saying.

It doesn't matter if the arrow is 40 inches long, or 27 inches long, when you put them on the spine tester they will read whatever the deflection is.

Yes, an arrow that is shortened or made extra heavy on the front will change dynamically, but the spine on the spine tester does not change.

[ozy clint]

they might group well, but are they flying good? i couldn't care less what the static spine is, the only thing i'm concerned about is dynamic spine which translates to how they fly.

i scrape with a sharp knife then when it's right i  give it a quick sand with paper.

if i weakened dynamic spine by leaving the arrow long and adding increasingly heavier points i would end up with 1000gr spears.

[Todd Mathis]

Huh.  Ok.  In over 300 arrows, I don't have any that weigh a fraction of that.  When the arrows all group in a saucer sized pattern, the dynamic spines are similar.  That would be your proof.  But If you haven't a clue what the static spine is, how would you know what head to glue on or length to cut to?  If you want to take some of the wood off the spine, I guess that is one way to weaken it.  but since bamboo has internal flaws that you can't see...well, good luck with that.

[ozy clint]

cavemen had static spine testers? i think not.
through experience they would have developed a feel for what was close to the spine they needed. the trick is to start out a little over spined then scrape it into tune.

i don't need to know the static spine before i cut it or decide what weight point to use. i cut it to what length i want and choose the point weight based more on achieving a desired total arrow mass after weighing the shaft. the dynamic spine is then adjusted via scraping to achieve good arrow flight. being able to shoot arrows of different point weights into a saucer sized pattern is as you say, proof that it works for me.

[ozy clint]

Originally posted by Todd Mathis:
for me, if they group in a saucer sized group at 20 yards, they are spined well enough for me.  since I shoot with a thumb ring, if the arrow hits to the right of the group, the spine is too strong.  I just put on heavier head.  It the arrow hits left of the group, I put on a lighter head.

i think we are looking at the problem from different perspectives, you from the perspective of how arrows are generally tuned today and myself from a primitive standpoint.

if i'm a caveman trying to survive i'm not going spend precious time and energy knapping another point of a different weight (remember a caveman didn't have grain scales anyway) in the hope that it turns out heavier or lighter so i can try it on my stiff or weak arrow.

to a caveman "just put on a heavier head" isn't the simplest solution. altering the dynamic spine via scraping of the arrow he just spent all day making is the simplest.

[LongStick64]

Personally I have found that I didn't need to be so exact when it came to bamboo arrows to get them to fly extremely well. I used shafts from Kustom King and they took more work to setup, but they worked as well as any other shaft I have used.
As Ozy points out our Primitive cousins probably didn't have much to judge the arrow on besides the perception of the arrows flight. I look at the huge arrows that the native South American people use today and I am amazed over their size, take a look on how they fly and we'd all criticize the arrow flight, but hell it works for them shooting monkeys out of trees and fish out of water.

[Pat B]

I only spine test cane and hardwood shoot shafts to find the stiff side which goes against the bow. Both my cane and sourwood shoot shafts are about 3/8" at the point end and 5/16" at the nock. This is on a 30" arrow and I shoot them from bows that are 50# to 60#@26".

[Todd Mathis]

I agree with you on the different point of view.  I have to say, after watching an arrow shatter and go through someone's hand (not a bamboo arrow) it got my undivided attention!  For a newbie just starting out, (which is what my website is all about) I'm thinking safety over what a primitive archer would do.  I agree with you.  If it is scrape or starve, I'm scraping too!  All good points!