Author Topic: Bows built backwards?  (Read 3459 times)

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Offline Morgan

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Bows built backwards?
« on: March 17, 2017, 03:28:04 pm »
In TBB vol 2 there is a chapter on ancient European bows. In this chapter it talks about the holmgaard bow and what they are calling the backward bow. The cross section diagram of these two bows look to be saplings cut up the middle with the inside of the tree being the back of the bow producing grain much like quarter sawn boards. I think this design would be awesome on 3" diameter staves. The writing says however that the bows from this time were tillered on back and belly resulting in grain peaks on the back of the bow. On page 107 it shows the back of two bows built like this that show what is in my opinion grain orientation that is just begging for disaster.
Do y'all see any issue in a bow built like this only keeping the grain lines on the back completely parallel and tillering from the belly alone as a normal bow is tillered?
The bows on page 107 say there is no problem with the grain with the length and evenness of the limbs, I can't help th think though that this is the exception and not the rule.
Thoughts?

Offline bushboy

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Re: Bows built backwards?
« Reply #1 on: March 17, 2017, 03:38:18 pm »
I wouldn't decrown a stave,only as a last resort maybe.
Some like motorboats,I like kayaks,some like guns,I like bows,but not the wheelie type.

Offline bradsmith2010

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Re: Bows built backwards?
« Reply #2 on: March 17, 2017, 04:04:03 pm »
i think we would see more of that ,,,, if it was such a great idea,,
that whole chapter really confused me as a new bow maker,, but,, I am sure it can work,, I dont think its gonna handle a high stress design,,
   if you keep the grain paralell,, it would be like a board bow right, so should not be a problem,,, I just never had an interest in experimenting with it, and really havent seen many people try it in the 30 years I have been making bows,, I am not really sure I believe it was a wide spread design, with the handle backwards,,???? 

Offline PatM

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Re: Bows built backwards?
« Reply #3 on: March 17, 2017, 04:10:47 pm »
That chapter has had a complete about face and is no longer viewed as accurate by anyone, including the author.

Offline bubby

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Re: Bows built backwards?
« Reply #4 on: March 17, 2017, 04:57:06 pm »
I'm pretty sure a few years back there was an article in PA where pappy and Gary Davis both built backwards osage bows
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Offline bradsmith2010

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Re: Bows built backwards?
« Reply #5 on: March 17, 2017, 05:29:51 pm »
thanks Pat, that makes me less confused,, :BB

Offline osage outlaw

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Re: Bows built backwards?
« Reply #6 on: March 17, 2017, 05:31:18 pm »
I'm pretty sure a few years back there was an article in PA where pappy and Gary Davis both built backwards osage bows

I believe they chased a ring on the belly of the stave and used that as the back of the bow. 
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Offline Pat B

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Re: Bows built backwards?
« Reply #7 on: March 17, 2017, 05:32:49 pm »
That was Gary and Pappy I think.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Stick Bender

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Re: Bows built backwards?
« Reply #8 on: March 17, 2017, 06:09:34 pm »
The Turk composite bows are built back wards , I will have some deflexed osage splits that are deflexed that I was thinking about chasing a belly ring and sinew and use the natural deflex as reflex I dont see why it wouldnt work , but never did it.
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mikekeswick

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Re: Bows built backwards?
« Reply #9 on: March 18, 2017, 01:42:57 am »
The Turk composite bows are built back wards , I will have some deflexed osage splits that are deflexed that I was thinking about chasing a belly ring and sinew and use the natural deflex as reflex I dont see why it wouldnt work , but never did it.

The wood in a composite is there to give the required shape to the bow and stability because the wood is stiffer than the horn or sinew layers. The reason the grain orientation is how it is - is so it can be steam bent into the tip reflex and the kasan eye reflex without breaking. The cores don't break because the wood is being bent with a single growth ring on the outside of the bend taking the tension. So whilst in the finished bow the core has 'backwards' grain, the core is only feeling sheer forces, if it were to feel tension it would break straight away. The back of the core has heavily violated grain due to the shaping process.

That chapter in TBB2 is completely wrong and was based on the assumption that the Holmguaard ows were built backwards - they were not. You can pretty much ignore that chapter.

Offline willie

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Re: Bows built backwards?
« Reply #10 on: March 18, 2017, 12:08:56 pm »
Quote
Do y'all see any issue in a bow built like this only keeping the grain lines on the back completely parallel and tillering from the belly alone as a normal bow is tillered?

There seems to be times where there could be some advantages using vertical grain, rather than flat grain on the back of a bow.
I do not see why your idea wouldn't work. I would try to work from a split center/back rather than sawing, though, as you might be fooled by a stave that would otherwise split as a propeller.

There must have been some observations of the artifacts that started the original discussion. Can the grain peaks on the back be attributed solely to bowyer? Most would agree that it's not the best practice, but perhaps the artifact was worn into that condition somehow?

It's worth a try, if for no other reason than to see what happens. Nothing ventured, nothing gained, as some say. You seem to have given some good thought as to how it might best be done.

 

Offline Morgan

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Re: Bows built backwards?
« Reply #11 on: March 18, 2017, 12:32:10 pm »
Thanks for all the replies. I bet I've read that chapter half a dozen times and it never made sense to me. I can definitely see where a stave that is split up the middle as willie suggests. Would make a fine bow. It should be as good as the very best grained board you could pick to use I would think. I have a gob of staves to start working on soon, but this is on my list of things to try.

Offline Badger

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Re: Bows built backwards?
« Reply #12 on: March 18, 2017, 02:31:52 pm »
    If the bow was made from elm there is a good possibility that the bowyers determined there was any need to worry about violations or runouts. I have seen elm bows that would tolerate most anything.

Offline Strichev

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Re: Bows built backwards?
« Reply #13 on: March 19, 2017, 04:11:40 am »
Didn't Ötzi also have a reverse bow made (or being made) out of yew? I plant to use a highly deflexed yew stave I have for a backwards heartwood only longbow.

Offline willie

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Re: Bows built backwards?
« Reply #14 on: March 19, 2017, 09:39:11 am »
split up the middle could be doable with a 3"stave, but I see no reason that the decrowning could not be off center, if you needed to get a better width for the belly, especially using a smaller sapling.