Where do they break?

[JW_Halverson]

I have some doubts as to whether I have ever given a passing whimsical thought to which end of a stave may or may not be stump end.  Furthermore, once I have a centerline chased and the stave narrowed down, I guarantee I have forgotten which end is which.  Granted, I may be a bit more absentminded than the average severe brain trauma victim.

But to assert that most of us build our bows by consciously choosing the bottom limb to be the stump end is frankly...going out on a limb.  Pure conjecture backed only by personal anecdotal evidence unless you can provide copy of your research including a statistically significant database of bowyers that you have canvassed and the numbers of bows that have been verified as being built stump limb down.   

[bubbles]

How do boards come in to play here?

[WillS]

I was about to mention boards.  Surely nobody can tell which end was which in a tree when looking at a board?

Out of all you guys who have broken a top limb, how many were boards and how many were staves?  Wouldn't that (if the numbers were similar) attribute more to how the bows are tillered than how the wood was hanging around when somebody chopped it's head/feet off?

I reckon it's just a coincidence.  Or aliens.

[Marc St Louis]

I think there's a few here who hasn't quite figured things out yet. Here's something that Dean Torges wrote in his article " Tillering the Organic Bow":

"As an aside, this might be the place to mention that the reason sister billets were preferred by past masters over full-length staves is that the wood is nearly identical limb to limb. Its working properties therefore are nearly identical. By contrast, if you sift through a stack of full length osage staves you will discover in each one dramatic differences in the growth rings from one nock end to the other. Selfbows of ring porous wood seldom resemble each other not only when made from staves taken from the same tree, but even within themselves, from one end to the other in a full length stave. It may be easier to build a bow from a full length stave rather than having to join sister billets at the handle, but it is simpler not to".

So positive tiller or where the arrow pass is located has nothing to do with the top limb failing. It's about the differences in working properties from one end of the stave to the other. Trunk end of the tree will be denser, stronger and have fewer defects. As you move up the tree the reverse is true............Art

Ah so we are back to that one again Art.  I do believe I disagreed with you the last time and I still do.  It may be different with Osage, which doesn't grow up here, but white-woods up here have less dense growth near the stump.  You can tell this by the growth rings being thicker at the stump end.  In fact I made a short Elm bow not long ago that had that exact problem.  The stump end had thicker rings and was taking more set than the other end, I fixed it with some heat-treating.

[artcher1]

WillS, it's very easy to tell how most board lays in a tree by studying it's growth rings from end to end. Well, except for pipe straight trees anyhow.

JW, sure, most of these guys build their bows as it stands in the tree. Haven't you read where everyone's upper limb is breaking .

Yeah, I remember our last exchange Marc. We'll just have to agree to disagree on this subject. But can you explain why, when our bows breaks, it's generally the upper limb? To date, I've heard of no other reasonable explanation then what I've given.  But I'll keep an open mind to what you and others have to offer in the way of a viable explanation on this matter.........Art

[WillS]

WillS, it's very easy to tell how most board lays in a tree by studying it's growth rings from end to end. Well, except for pipe straight trees anyhow.

Yeah but... Are you saying most guys check for that?  I know it can be done, that's not the point.

How many bowyers on here for example when starting a board bow check both ends to see which would have been lower in the tree, and use that for their lower limb?

[artcher1]

With boards, you're not dealing with knots and imperfections and such. So why would it even dawn on someone to even consider this?  And if you're making board bows, then you're probably new at this game, and shouldn't, at this point, even being concerned with uneven working properties. I would think, just building a serviceable bow at this point, would be more important.

Staves, on the other hand, off their own challenges.......Art

[Marc St Louis]

Yeah, I remember our last exchange Marc. We'll just have to agree to disagree on this subject. But can you explain why, when our bows breaks, it's generally the upper limb? To date, I've heard of no other reasonable explanation then what I've given.  But I'll keep an open mind to what you and others have to offer in the way of a viable explanation on this matter.........Art

Positive tiller is one plausible explanation.  I read how one person believes that the lower limb is more stressed but I'm afraid I disagree with that one as well.  If you look at a bow with a positive tiller you will see that it has a slightly steeper string angle which means that limb is bending more.  More bend = more stress.  I'm not saying that this is positively the reason, I don't really know as I don't break bows 

[bushboy]

art please direct me to this magic flawlist pile of boards of which you speak. .maybe one out of 30 boards have a chance at all.ive only made a few stave bows but i tend to think they are alot tougher than any board i have ran across so far.yes 95% of my failures ,which has been many have been on the upper limb when i had my arrow rest high ,now i go between 3/4" to 1" above center and break alot less nowadays

[ionicmuffin]

the one I broke was on the top limb, It hit my head, maybe thats why I'm just nuts.

[Marks]

I've noticed in a lot of 'money shot' pictures that the upper limb seems to be pushed out in front of the bottom limb. Maybe the natural shape of your hand with the thumb on top cause you to push the upper limb harder than the bottom. I posted the December BOM thread. Not all look like this but #4, 5, 8,9, and 12 all look to me like the top limb is leading the bottom limb.  I also posted Slimbobs recent bow. Hope yall don't mind being used as an example. I'm new to this sport so I'll let yall confirm or debunk my theory.

http://www.primitivearcher.com/smf/index.php/topic,44457.0.html
http://www.primitivearcher.com/smf/index.php/topic,44825.0.html

I guess my 2 cents didn't make sense since it wasn't acknowledged.

[bubbles]

Hahah, iconicmuffin,  those damn top limbs! I'm with you that.  It would be interesting to see if Yumi's break in the top or bottom limb typically, just because of the extreme asymmetry.

[Crogacht]

I think if I attempted a yumi, they'd all break everywhere at the same time   

[WillS]

With boards, you're not dealing with knots and imperfections and such. So why would it even dawn on someone to even consider this? 

Yes.  Exactly my point.  Nobody considers it.  So you can't say there's a link can you?  If nobody knows which limb was topmost in a tree, you're saying that it's the most amazing fluke that they all choose the same limb as the top limb in their bow.

And if you're making board bows, then you're probably new at this game, and shouldn't, at this point, even being concerned with uneven working properties. I would think, just building a serviceable bow at this point, would be more important.

Wow.  Isn't that a touch... Elitist? There are guys on here who've been making bows for countless years who still turn out sensational board bows.  I think this is the first time I've ever read on here that attitude towards one type of bow making - and it's not cool.  I've never made a board bow because in the UK it's much harder to find decent timber compared to staves of excellent bow wood, but I'm looking forward to trying a board bow one day.  I guess I won't be asking you for an opinion on one if I do make it though right?

[DavidV]

If there's an iffy limb I put it on the top so if it breaks it hits me on the head rather than other sensitive areas... my priorities have always been a little out of whack XD