Well that went badly. . .

[Aaron H]

Also those spine calculators are based on the assumption that your points are 125 grain.  A heavier point will also reduce spine, another contribution to your arrows being spined too weak.

[make-n-break]

Sounds to me like false weak, as others stated. Your shaft is likely bouncing off the shelf kicking it way left.

[bubbles]

I do my bareshafting starting at 5 yards and moving out if I have a good arrow that's shooting well.  Wood arrows tend to break if they hit too angled.  Also what helps is a layered target with the layers going horizontally.  It can allow the arrow to slide in on an angle a bit easier.

[jeffp51]

The box I am shooting at is filled with horizontal layers of cardboard,  Having been shot at so much, it is pretty soft at the moment.

I have two remaining bare shafts.  I will try adding more weight to one tip first.  That should answer the false weak theory.

[DC]

You can start your bare shaft test at half draw or less. See how it flies. Then start increasing your draw a bit at a time. If at any time the arrow goes nock left it's too limp. This method doesn't give any better results but you won't break arrows. Especially with a 55# bow.

[le0n]

You can start your bare shaft test at half draw or less. See how it flies. Then start increasing your draw a bit at a time...

^^ this is very good information.

also, a good bamboo shaft should hold up to a fair amount of stress. the way those arrows fractured almost implies that the material is too brittle or that the integrity has been compromised in some way (excessive heat treating?) some of those garden stakes are too dry to begin without heat treating. some of the better quality ones can almost be bent into a "U" shape before they snap.

the arrow in the target failed at the node, it appears like a clean break with no long-running splinters. did you sand the nodes?

i'd be inclined to believe those particular shafts almost failed as they left the bow, so be careful with the remaining shafts from that package.

[DC]

I think this was a combination of things. A heavy(ish) bow, long arrows and heavy tips. All of these effectively reduce the spine and you end up with kindling. I'm not sure how many boo arrows Jeff has made but when I made my first ones any that broke, broke at a node. I think it takes a little experience to straighten the kink at the node without overstressing it. I think with a 55# bow and 32" arrows I would try a deflection of around .3-.35". I made a set of test arrows just for this purpose. Six unfletched arrows between 30 and 50# spine(.5-.8" def) 125 grain point. When I make a new bow I start with the heaviest first. If it hits nock right, I work my way down until it goes straight. I don't use them much now because most of my bows are in the low 40's and I know what spine works for them. It still changes a bit bow to bow.

[jeffp51]

The nodes are sanded--never had one break at a sanded node before--but they were also from a batch of bamboo bought some time ago, and were noticeably dryier than other shafts I have worked,  although I managed to straighten them all without scorching them.  Just bought a whole bunch more last night for the "do-overs"  These look greener and I hope they will be sturdier.

DC  I have made close to 50 bamboo arrows at this point, and I do feel like I am getting better at the straightening part of the process.  I think it is more the other things you mentioned that are causing the problem.

As for the false-weak theory--would not the arrow make a loud whacking sound as it hits the bow if it were actually strong and just being kicked wide?  I don't recall hearing that last night, but I wasn't really listening for it either.

[DC]

I know people with much more smarts than me say to not sand nodes but when I started I found I had a bunch of nice shafts in the 50-70# range that I had no use for. I put them in my drill and spun it up while holding it against my belt sander. I just kept going until they were in the 40# range. They are beautiful and straight and (touch wood) none have broken.  Between this and watching the Japanese Master video many, many times and seeing him cutting off the nodes and sanding a lot I just feel it's not that big a deal. Mind you, you have to get the shaft dead straight before you start to sand or you will get a thin spot.

I have also made about 50 or so arrows so we're in about the same spot on the learning curve.

[le0n]

Just bought a whole bunch more last night for the "do-overs"  These look greener and I hope they will be sturdier.

sounds better already

you can always make one of these green ones with the same specs as your last batch, repeat the test.

good luck!

[aaron]

Wait... did someone say thumbring.? How exactly are you shooting and off what side of the bow. .?

[Urufu_Shinjiro]

Wait... did someone say thumbring.? How exactly are you shooting and off what side of the bow. .?

That would be Loon and me, Jeff is shooting normally.