40,5" Hickory 65#@20"

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Archiv
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40,5" Hickory 65#@20"

Beitrag von Archiv » 12.10.2005, 17:48

Die "Backyard Bowyers" haben einige interessante Bögen auf ihrer HP und weil im Leatherwall gerade einer davon vorgestellt wurde, dachte ich mir, ich frage mal die hiesigen Bogenbauinfizierten nach ihrer Meinung.

Es geht um diesen Bogen aus Hickory, der 40,5" lang ist und bei einem Auszug von 20" ein Zuggewicht von 65# hat.

Bogen aufgespannt
Bogen im Vollauszug

Den Tiller finde ich schon etwas ungewöhnlich...was meint ihr?

Taran
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Eindeutig ein Rohan-Reiterbogen...

Beitrag von Taran » 12.10.2005, 19:24

Bei so starkem Deflex ist es nicht leicht zu beurteilen, ob hier wirklich die Wurfarme arbeiten, oder der Bogen zu stark in der Mitte biegt.
Ich will mal versuchen, die Bilder übereinanderzulegen.
Taran von Caer Dallben

... και δόξα τω Θεώ !

Holzbogenbauer
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Beitrag von Holzbogenbauer » 12.10.2005, 19:35

also wenn das Ding (ich will nicht Bogen sagen) nicht weh tut und einen schön durchrüttelt, fass ich nie wieder einen Stave an. Außerdem schaut es wie Eibe mit Hickory gebackt aus.

Taran
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Also hier der Beweis

Beitrag von Taran » 12.10.2005, 20:02

[url=http://www.fletchers-corner.de/cpg/albums/userpics/10321/statictotal.jpg]
Bild[/url]

Die Wurfarme arbeiten schon, aber die Biegung im Griffbereich scheint mir viel stärker zu sein.
Ein schöner Beweis dafür, was Hickory so alles aushält, aber man müsste schon eher einen Kreisbogentiller anstreben!
Taran von Caer Dallben

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Mika
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Beitrag von Mika » 12.10.2005, 20:02

Sorry no comment. Thats old stuff

Taran
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Hi Mika

Beitrag von Taran » 12.10.2005, 20:08

Of course short draw brush-bows are a lot of fun. A 600 grain arrow is a rather heavy one, so that ought to "tame" the bow. If you want to improve it, I'd suggest making the limbs bend more, as my photo overlays suggest that most of the bending takes part in or very near the handle. A more circular tiller seems to be advisable.

Might also increase the bow's lifespan.

Work towards a circular tiller, lose 10 lbs and use lighter arrows - you won't lose any performance, but improve it, I guess.

But first of all, congratulations on pulling off this stunt, the bow IS beautiful and a lot of other people would have broken it.
It is just hickory without any backing, I gather?
Froam a board or a tree? What's the grain orientation?
Taran von Caer Dallben

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Mika
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RE: Hi Mika

Beitrag von Mika » 12.10.2005, 20:33

Sorry no comment. Thats old stuff.

Archiv
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Beitrag von Archiv » 12.10.2005, 20:39

Taran, saubere Sache das mit den Fotos.
Auf weiteren Fotos auf Mikas Seite kann man erkennen, dass der Bogen ein Hickory/Hickory-Laminat ist und interessanterweise einen dreieckigen Wurfarmquerschnitt hat, bei flachem Rücken.

Mika, great to see you here at FC! :knuddel

Mika: a more circular tiller would not only destress the handle section but might also enable you to pull the bow another inch or two.
I am sure the bow´s performance would increase a lot and somewhat lighter arrows fly even further and/or faster.

Taran
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RE: RE: Hi Mika

Beitrag von Taran » 12.10.2005, 20:49

Original geschrieben von Mika
I made too thick lamination that i was beable to make any lighter pounds for bow.



I dont count the grains while i cant select hickory what can get.


Hello Mika, I'm sorry, but I can't make out the meaning of the first sentence at all.

As to the second sentence: That's a misunderstanding. I would like to gnow the orientation of the grain, that is: is it flat (parallel to the back) or at an angle to the back?
Taran von Caer Dallben

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Mika
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RE:

Beitrag von Mika » 12.10.2005, 20:54

Sorry no comment. Thats old stuff.

Taran
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Don't get annoyed

Beitrag von Taran » 12.10.2005, 21:02

No I have not made a bow like this, no, I have not made a bow like this with such thick limbs, no, I would never have attempted such a profile.

I told you I appreciate what you have done. If you are not interested in my honest opinion, don't ask.

I do NOT want you to lengthen the draw, I agree with you that that might spell D-E-S-A-S-T-E-R !!!
With that kind of triangular profile and a belly narrower than the back I am very worried about the strain put on the grip area, because the bend is not distributed evenly.
I have my history of tillering errors, and my experience, for what it's worth, is, that such a bow shoots well for a while, but then there may either be excessive set or chrysals, reducing the efficiency or even tolling the death-bell for the bow.
I do not know why you wanted to build such a short bow with such a high draw weight for such heavy arrows and such an unusual profile and such a tiller.
You've been pushing the limits - and your luck, and so far your luck has held and that proves you a very good bowyer.
I just suggested some things might be done in a different way next time.
Okay? :knuddel
Taran von Caer Dallben

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Mika
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RE: RE: RE: Hi Mika

Beitrag von Mika » 12.10.2005, 21:07

Sorry no comment. Thats old stuff.

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kra
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RE: RE: Hi Mika

Beitrag von kra » 12.10.2005, 21:39

Original geschrieben von Mika
...
Thats made from 3 piece lamination including backing and all hickory. For any longer draw is needed bamboo or sinew for backing but while compression of sinew or bamboo may broke easily hickory belly too i dont recomended use bamboo or sinew with hickory in anyway.

Addin bamboo or sinew into back cause many times shorter life for short hickory bow too.


Hi Mika, one question regarding sinew. As I understood till now, one benefit of sinew is that it will stretch unter tension mutch more than wood. So I would expect that when using sinew backing on a wooden belly most energy is stored in the sinew while the stress in the wood is lower.

For bamboo I see it opposite: as bamboo can take en extreme tension with a relative small elongation it would (and in fact does) crunch a wooden belly if it is too thick.

Nevertheless, the bow you showed is an extreme example waht hickory can take. Do you have some figures about speed with different arrows weights?
“Was wir brauchen, sind ein paar verrückte Leute; seht euch an, wohin uns die Normalen gebracht haben.”
– George Bernard Shaw

Taran
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So far so good

Beitrag von Taran » 12.10.2005, 21:46

That's much clearer now: You can't change the tiller any further because you would cut through your belly laminations.

So I asked, so I got an answer. Fine!

You quote Tim Baker and the Bowyer's Bible. Both of us have probably seen that fantastic short maple selfbow depicted in the "Design and efficiency" chapter. That's the tiller shape I was thinking of.

And he clearly states how important it is to use libs that are as rectangular as possible.

So, according to the fine pictures on your site, you have built a high, sharp ridge on the belly. Why? This, according to Baker and other people with a lot more experience than both of us put together, is not a good idea, further concentrating stress loads. You know the "gurus", you do have experience, so I ask you why you chose that design. You could most probably have reached the same draw weight with two laminations, a wider limb, and a rectangular profile, resulting in a lighter bow with a wider safety margin.

I see much tillering experts here but how many of you are made bow like that and where is that bow ? How many have made even close 50" and 70# because then you may release that thats not the same as make longer ones


That's what you wrote, and that sounded like a challenge to me, so I took up the gauntlet - because I want to learn. I know you from the days when we were on PA together, and I know you do things for a reason. But as long as you don't tell us we can just shake our heads in wonder.

BTW: What glue did you use?
Have you had any chance to test the speed of the bow yet?
Taran von Caer Dallben

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Mika
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RE: RE: RE: RE: Hi Mika

Beitrag von Mika » 12.10.2005, 21:47

Sorry no comment. Thats old stuff.

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